Every File Extension
Known in the
World
Every File Extension Known in the World
 
A 
A	Object code library
A	Library file (Unix)
AA	Audible audio file (commonly used for downloadable audio books)
AAM	Authorware shocked file
AAS	Authorware shocked packet
AB	Applix Builder file
ABF	Adobe Binary Screen Font
ABK	Backup file (PrintMaster Gold)
ABK	Data backup file (Avigo)
ABK	Corel Draw AutoBackup
ABM	Audio album file (HitPlayer)
ABM	Album file (Image), (PALS)
ABO	Applix Builder Turbo file
ABR	Brush file (Adobe PhotoShop)
ABS	MPEG Audio Sound file
ABS	Standard GNU compiler output file for a PC platform
ABS	Sometimes used to denote an abstract (as in an abstract or summary of a scientific paper) AutoBackup
ABS	Data file (Abscissa)
ABW	Document file (AbiWord)
AB$	Plot file spooled for printer (AutoCAD AutoSpool)
ACA	Project Manager Workbench file
ACA	HTTP animation file (Microsoft Agent)
ACAD	Database file (AutoCAD)
ACB	ACBM Graphic image 
ACB	Archived data file (ACB)
ACC	DR-DOS Viewmax file
ACD	Character definiton file (Microsoft Agent)
ACE	ACE Archiver Compression file
ACF	HTTP character file (Microsoft Agent)
ACF	Adobe custom filter (Adobe PhotoShop)
ACGI	WWW script file
ACI	ACI development appraisal (ACIWEB)
ACL	Corel Draw 6 keyboard accelerator file
ACM	Windows system directory file
ACM	Interplay compressed sound file (Fallout 1,2, Baulder's Gate)
ACM	Dynamic Link Library (DLL)
ACM	Add-on file for Audio Compression Module(s),(Microsoft Windows Codecs)
ACM	Image file (ACBM)
ACMB	Image file (ACBM)
ACO	Colour Palette (Adobe PhotoShop)
ACP	Microsoft Office Assistant Preview file
ACR	American College of Radiology file
ACS	Character structered storage file (Microsoft Agent)
ACT	Microsoft Office Assistant Actor file
ACT	FoxPro Foxdoc Action Diagram
ACT	Action Presentation
ACT	Source code file (Actor), (Graphics cell, and others)
ACT	Documenting wizard action diagram (Microsoft Visual FoxPro)
ACT	Colour Table (Adobe PhotoShop)
ACV	Used to Compress and decompress audio data
AD	After Dark screensaver
AD2	2-bit compressed voice file (ADCPM), (ZFAZ), (used in voice, data,fax transmisiions)
AD3	3-bit compressed voice file (ADPCM), (ZFAX), (used in voice,data,fax transmissions)
ADA	Ada source text file (non-GNAT)
ADB	Ada source text body file (GNAT)
ADB	HP 100LX Organizer Appointment database
ADC	Scanstudio 16 color Bitmap Graphic file
ADC	Dictionary text file (Lingvo)
ADD	OS/2 adapter driver file used in the boot process
ADE	Audio file (ADC,TI/MIT)
ADEX	Image file (Bitmap), (ADEX Corp)
ADF	Amiga disk file
ADI	AutoCAD device-independent binary plotter file
ADI	Graph file (AutoCAD)
ADL	QEMM Mca adaptor description library
ADM	After Dark MultiModule screensaver (Microsoft)
ADM	Windows NT policy template
ADN	Lotus 1-2-3 Add-In file
ADP	Dynamic Page file (AOLserver)
ADP	FaxWorks Faxmodem setup file
ADP	Astound Dynamite file
ADPCM	Audio codec (Intel/DVI adaptive differential pulse code modulation) 
ADR	After Dark Randomizer screensaver
ADR	Smart Address address book
ADS	Ada source text specification file (GNAT)
ADT	HP NewWave datafile for card applications
ADT	AdTech Fax file
ADT	Dictionary data file (Lingvo)
ADV	Virtual device driver (VXD), (GUS)
ADX	Dynazip Active Delivery script
ADX	Lotus Approach dBase Index
ADX	Archetype Designer Document
ADZ	Packed ADF file (Extracts with WinZip)
AE	Author/Editor file (SoftQuad)
AEP	ArcExplorer project filehttp://www.esri.com/software/arcexplorer/index.html
AEX	Armored extracted public encryption key (PGP)
AEXPK	Armored extracted public encryption key (PGP
AF2	ABC FlowCharter 2.0 Flowchart
AF3	ABC Flowchart
AFC	Apple Sound file
AFI	Truevision Bitmap graphic
AFM	Adobe font metrics
AFM	HP NewWave Cardfile application
AFP	Graphics file (IBM)
	
AG	Applix graphic
AI	Adobe Illustrator drawing
AI	Corel Trace drawing
AIF	Audio Interchange File, a sound format used by Silicon Graphics and Macintosh applications
AIFC	Similar to AIF (compressed)
AIFF	Similar to AIF
AIM	AOL Instant Messenger Launch file
AIN	AIN Compressed archive
AIO	APL transfer file
AIS	ACDSee Image Sequence
AIS	Velvet Studio Instruments file
AIS	Xerox Arry of Intensity Samples Graphic
AIX	HP NewWave Cardfile Application data
AKW	Contains all A-keywords in the RoboHELP Help Project Index Designer not associated with topics
ALAW	European Telephony audio
ALIAS	Alias Image
ALB	JASC Image Commander album
ALI	Document file (SAP proprietary format)
ALL	Arts & Letters Library
ALL	WordPerfect for Windows General printer information file
ALS	Alias Image
ALT	WordPerfect Library Menu
AM	Applix SHELF Macro
AMF	Music file (Advanced Module Format)
AMF	DSMIA/Asylum module music (Crusader,No Remorse,Aladdin)
AMG	AMGC Compressed archive
AMG	ACTOR System image
AMI	Annotation file (Cocreate SolidDesigner)
AMS	Velvet Studio music module (MOD) file
AMS	Extreme's Tracker module
AN	Text file (Sterling Software) (Groundworks COOL Business Team Model)
ANC	Canon Computer Pattern Maker file that is a selectable list of pattern colors
ANI	Microsoft Windows Animated cursor
ANM	DeluxPaint Animation
ANN	Windows 3.x Help annotation
ANS	ANSI Text file
ANT	SimAnt for Windows saved game
AOS	Nokia 9000 Add-on software
AOT	Applicatio binary object template file (ZenWorks snAPPshot)
AP	Applix Presents file
AP	WHAP Compressed Amiga archive
APC	Compiled application file (Centura Team Developer)
APC	Lotus 1-2-3 Printer driver
APD	Dynamic application library file (Centura Team Developer)
APD	Lotus 1-2-3 Printer driver
APF	Lotus 1-2-3 Printer driver
APF	Project file (Allaire) (Created by Homesite)
API	Application Program Interface; used by Adobe Acrobat
API	Lotus 1-2-3 Printer driver
APL	Application library file (Centura Team Developer)
APL	APL Workspace file
APP	Normal mode application file (Centura Team Developer)
APP	Symphony Add-in Application
APP	Generated application or active document (Microsoft Visual FoxPro)
APP	dBase Application Generator Object
APP	DR-DOS Executable Application
APP	FoxPro Generated Application
APR	ArcView project file <>
APR	Employee Appraiser Performance Review file
APR	Lotus Approach 97 View file
APS	Microsoft Visual C++ file
APS	Advanced patching systems with error checking, (Similar to IPS)
APT	Lotus Approach Data view file
APT	Text mode application file (Centura Team Developer)
APX	Lotus Approach Paradox-Specific information file
APX	Borland C++ Appexpert database
AQ	Applix data
ARC	LH ARC (old version) compressed archive
ARC	SQUASH Compressed archive
ARF	Automatic Response file
ARI	ARI Compressed archive
ARI	Aristotle audio file
ARJ	Robert Jung ARJ compressed archive (ARJ)
ARK	ARC File Archiver CPM/Port archive
ARL	AOL v4.0 organizer file
ARR	Atari Cubase Arrangement
ART	Xara Studio drawing
ART	Canon Crayola art
ART	Clip Art
ART	Ray Tracer file
ART	First Publisher Raster graphic
ART	AOL Image file compressed using the Johson-Grace compression algorithm
ARX	ARX Compressed Archive
AS	Applix Spreadsheet
ASA	Microsoft Visual InterDev file
ASC	ASCII text file
ASC	PGP armored encrypted file
ASD	WinWord AutoSave file
ASD	Lotus 1-2-3 Screen driver
ASD	Microsoft Advanced Streaming Format (ASF) description file; opens with NSREX
ASD	Astound Presentation
ASE	Velvet Studio Sample file
ASF	Music file (Electronic Arts)
ASF	Microsoft Advanced Streaming Format
ASF	StratGraphics Datafile
ASF	Lotus 1-2-3 Screen font
ASH	TASM 3.0 Assembly language header
ASI	Borland C++/Turbo C Assembler Include file
ASM	Assembler Language source file
ASM	Pro/E assembly file
ASO	Astound Dynamite Object
ASP	Active Server Page (an HTML file containing a Microsoft server-processed script)
ASP	Procomm Plus setup and connection script
ASP	Astound Presentation
AST	Astound multimedia file
AST	Claris Works "assistant" file
ASV	DataCAD Autosave file
ASX	Cheyenne Backup script
ASX	Microsoft Advanced Streaming Redirector file
ASX	Video file
AT2	Aldus Persuasion 2.0 Auto Template
ATM	Adobe Type Manager data/info file
ATT	AT&T Group 4 bitmap
ATW	AnyTime Deluxe for Windows personal information manager file from Individual Software MultiModule screensaver
AU	Sun/NeXT/DEC/UNIX sound file
AU	Audio U-law (pronounced mu-law)
AUD	Audio file (Westwood Studios) (Kyrandia 3,C&C,RedAlert,C&C:TS)
AUX	TeX/LaTeX Auxilliary Reference file
AUX	ChiWriter Auxilliary Dictionary file
AVA	Avagio Publication
AVB	Inculan Anti-Virus virus infected file
AVI	Microsoft Audio Video Interleaved file for Windows movie
AVR	Audio Visual Research file
AVS	Application Visualization System file
AVS	Stardent AVS-X Image
AVX	File Extension (ArcView)http://www.esri.com/software/arcview/index.html
AW	HP AdvanceWrite Text file
AW	Applix Words file
AWD	FaxView Document image
AWK	AWK Script/Program
AWM	Animation Works Movie
AWR	Telsis file for digitally stored audio
AWS	StatGraphics Data file
AXL	ArcIMS XML project file http://www.esri.com/software/arcims/index.html
AXT	ASCII application object template (ZenWorks snAPPshot)
AXX	ARJ compressed file from a multi-volume archive (xx = a number from 01 to 99)
A3L	Authorware 3.x library
A4L	Authorware 4.x library
A5L	Authorware 5.x library
A3M	Authorware MacIntosh file (unpackaged)
A4M	Authorware MacIntosh file (unpackaged)
A4P	Authorware file (packaged without runtime)
A3W	Authorware Windows file (unpackaged)
A4W	Authorware Windows file (unpackaged)
A5W	Authorware Windows file (unpackaged)
 
B
B	Applause Batch list
BAD	Oracle bad file
BAK	Backup file
BAL	Ballade Music score
BAR	dBase Application Generator Horizontal menu object
BAS	BASIC source code
BAT	Batch file
BB	Papyrus Database backup
BBL	TeX/BibTeX Bibliographic reference file
BBM	Deluxe Paint Bitmap image
BBS	Bulletin Board Sytem text
BCH	Batch Process Object (dBase Application Generator)
BCH	Datalex Entry Point 90 Data file
BCM	Microsoft Works Communications file
BCO	Bitstream Outline font description file
BCP	Borland C++ Makefile
BCW	Borland C++ 4.5 Environment settings file
BDB	Microsoft Works Dababase file
BDF	West Point Bridge Designer file
BDF	Egret Datafile
BDR	Microsoft Publisher Border
BEZ	Bitstream Outline font description
BF2	Bradford 2 Font
BFC	Windows 95 Briefcase Document
BFM	Font Metrics file (Unix/Mainframe)
BFX	Fax document file (BitFax)
BG	Microsoft Backgammon Game file
BGA	OS/2 Graphic array
BGI	Borland Graphics Interface Driver
BGL	Microsoft Flight Simulator Scenery file
BHF	pcAnywhere Host file
BI	Binary file
BIB	Bibliography file (ASCII)
BIB	TeX/BibTeX Literature Database
BIB	Database
BIF	GroupWise initialization file
BIF	Image Capture Board Binary Image black & white graphic
BIFF	XLITE 3D file
BIN	Binary file
BIO	OS/2 Bios file
BIT	X11 Bitmap
BK	Backup file (Generic)
BK	JetFax Faxbook file
BK$	Backup file (Generic)
BK!	WordPerfect for Windows Document backup
BK1	WordPerfect for Windows Timed backup file for document window 1
BK2	WordPerfect for Windows Timed backup file for document window 2
BK3	WordPerfect for Windows Timed backup file for document window 3
BK4	WordPerfect for Windows Timed backup file for document window 4
BK5	WordPerfect for Windows Timed backup file for document window 5
BK6	WordPerfect for Windows Timed backup file for document window 6
BK7	WordPerfect for Windows Timed backup file for document window 7
BK8	WordPerfect for Windows Timed backup file for document window 8
BK9	WordPerfect for Windows Timed backup file for document window 9
BKP	TurboVidion Dialog Designer Backup
BKS	IBM BookManager Read bookshelf file
BKS	Microsoft Works Spreadsheet Backup
BKW	FontEdit Fontset mirror image
BLB	Resource archive (DreamWorks),(Neverhood)
BLD	BASIC Bloadable picture file
BLK	Alias Wavefront Image
BLK	WordPerfect for Windows Temporary file
BM	Windows system Bitmap
BMF	Corel Gallery file
BMK	Windows Help bookmark
BMP	Windows or OS/2 bitmap
BM1	Apogee BioMenace data
BN	Instrument bank file (AdLib)
BNK	Sound effects bank file (Electronic Arts)
BNK	Instrument Bank file (AdLib)
BOL	Compressed archive library file (Microsoft Booasm.arc)
BOM	Bill of materials file (Orcad Schematic Capture)
BOO	Microsoft Booasm.arc Compressed archive
BOOK	Adobe FrameMaker Book
BOX	Lotus Notes file
BPC	Business Plan Toolkit Chart
BPL	Borland Delphi 4 packed library
BPS	Microsoft Works Document
BPT	CorelDraw Bitmap fills file
BPX	Truevision Targa Bitmap
BQY	BrioQuery file
BR	Bridge Script
BRD	Eagle Layout file
BRI	Basic rate interface file
BRK	Brooktrout Fax-Mail file
BRW	Application file associated with financial institution(s) loan applications
BRX	A file for browsing an index of multimedia options 
BRZ	DbBRZ file for very large Db backup or restore
BSA	BSARC Compressed archive
BSC	Apple II Compressed archive
BSC	Fortran Pwbrmake Object
BSC	MS Developer Studio (MSDev) browser information
BSP	Quake map file
BS1	Apogee Blake Stone data file
BS_	Microsoft Bookshelf Find Menu shell extension
BTM	Batch file used by Norton Utilities
BTR	Database file (Btrieve 5.1)
BUD	Backup disk for Quicken
BUG	Bugs and Problems file
BUN	CakeWalk Audio Bundle (a MIDI program)
BUP	Backup
BUT	Buttons! Button definition
BUY	Movie data file
BV1	WordPerfect for Windows Overflow file below insert point in document 1
BV2	WordPerfect for Windows Overflow file below insert point in document 2
BV3	WordPerfect for Windows Overflow file below insert point in document 3
BV4	WordPerfect for Windows Overflow file below insert point in document 4
BV5	WordPerfect for Windows Overflow file below insert point in document 5
BV6	WordPerfect for Windows Overflow file below insert point in document 6
BV7	Wordperfect for Windows Overflow file below insert point in document 7
BV8	WordPerfect for Windows Overflow file below insert point in document 8
BV9	WordPerfect for Windows Overflow file below insert point in document 9
BW	SGI Black and White image file
BW	Silicon Graphics Raw red,green and blue bytes file
BWB	Visual Baler Spreadsheet application
BWR	Kermit Beware buglist
BWV	Business Wave file
BYU	BYU Movie
BZ	Bzip compressed file (Inix)
BZ2	Bzip compressed file (Unix) (replaces Bz)
B1N	1st Reader Mono and color binary screen image
B30	ABC Ventura publisher printer font
B4	Helix Nuts and Bolts file
B8	Raw graphic file (Piclab Plane II)
B_W	Atari/Macintosh black and white graphic
B&W	Atari/Macintosh black and white graphic
B&W	1st Reader Mono binary screen image
 
C 
C	C code
C	Site configuration for Secure Remote (CheckPoint VPN)
CA	Telnet Server Initial cache data file
CAB	Microsoft cabinet file (program files compressed for software distribution)
CAC	dBase IV Executable file
CAD	Softdesk Drafix Cad file
CAG	Catalog file (Microsoft Clip Gallery v. 2.x,3.x,4.x)
CAL	CALS Compressed Bitmap
CAL	SuperCalc 4/5 Spreadsheet
CAL	Calendar schedule+ data file (Microsoft)
CAM	Casio camera file
CAN	Navigator Fax
CAP	Ventura Publisher Caption
CAP	Compressed music file
CAP	Telix Session Capture file
CAR	AtHome assistant file
CAS	Comma-delimited ASCII file
CAT	Quicken IntelliCharge categorization file
CAT	dBase Catalogue file
CB	Microsoft clean boot file
CBC	CubiCalc Fuzzy Logic System file
CBI	Column binary file (used in IBM mainframe systems)
CBL	Cobol Source code
CBM	XLib Compiled Bitmap
CBT	Generic Computer based training file
CC	Visual dBASE custom class file
CC	C++ Source code
CCA	cc:mail archive file
CCB	Visual Basic Animated Button configuration file
CCC	Curtain Call Native bitmap graphic
CCE	Data file (Calendar Creator Plus)
CCF	Multimedia Viewer configuration file used in OS/2
CCF	Symphony Communications Configuration file
CCH	Corel Chart
CCL	Intalk Communication Command Language
CCM	Lotus CC:Mail "box" file (for example, INBOX.CCM)
CCO	CyberChat data file
CCO	XBTX Graphics
CCT	Macromedia Director Shockwave cast file
CDA	CD Audio Track
CDB	Clipboard file
CDB	CardScan Database (CardScan)
CDB	TCU Turbo C Utilities Main database
CDB	Conceptual model backup file (PowerDesigner)
CDF	Netcdf Graphic file
CDF	Microsoft Channel Definition Format
CDFS	Compact Disk filing system (WindRiver)
CDI	Phillips Compact Disk Interactive file
CDK	Atari Calamus Document
CDM	Conceptual model file (PowerDesigner)
CDM	Visual dBASE custom data module
CDM	Conceptual data model file (PowerDesigner Data Architect) (Sybase)
CDR	Corel Draw Vector drawing file
CDR	Raw Audio-CD data file
CDT	Corel Draw template
CDT	CorelDraw Data file
CDX	Corel Draw compressed drawing
CDX	Microsoft's Visual FoxPro index
CE	The FarSide Computer Calendar Main CE file
CEG	Tempra Show Bitmap graphic
CEL	CIMFast Event Language file
CEL	AutoDesk Animator Cel Image
CER	Certificate file (MIME x-x509-ca-cert)
CF	Imake Configurtion file
CFB	Comptons Multimedia file
CFG	Configuration file
CFL	CorelFLOW Chart
CFM	ColdFusion template
CFM	Visual dBASE Windows customer form
CFM	Corel FontMaster file
CFN	Atari Calamus Font data file
CFO	TCU Turbo C Utilities C form object
CFP	The Complete Fax Portable fax file
CGA	Ventura Publisher Display font file
CGI	Common gateway interface script
CGM	Computer Graphic Metafile
CH	OS/2 configuration file
CH	Clipper 5 Header
CH3	Harvard Graphics 3.0 Chart
CH4	Charisma 4.0 Presentation
CHD	FontChameleon Font descriptor
CHF	pcAnywhere remote control file
CHI	ChiWriter Document
CHK	File fragments saved by Windows Disk Defragmenter or ScanDisk
CHK	WordPerfect for Windows Temporary file
CHL	Configuration History Log
CHM	Compiled HTML file
CHN	Ethnograph Data file
CHP	Ventura Publisher Chapter file
CHR	Character Sets (Font file)
CHT	ChartViewer file
CHT	Harvard Graphics vector file
CHT	ChartMaster dBase Interface file
CIF	CalTech Intermediate Graphic
CIF	Easy CD Creator image
CIF	pcAnywhere caller file
CIF	Converted image file (Ventura Publisher)
CIL	Clip Gallery download package file
CIM	Sim City 2000 file
CIM	Cimpack design drawing file (CIMEX)
CIN	OS/2 change control file that tracks changes to an INI file
CIR	Save-file command (SuperMax E-CAD)
CIX	TCU Turbo C Utilities Database Index
CKB	Borland C++ Keyboard mapping file
CK1	iD/Apogee Commander Keen 1 data
CK2	iD/Apogee Commander Keen 2 data
CK3	iD/Apogee Commander Keen 3 data
CK4	iD/Apogee Commander Keen 4 data
CK5	iD/Apogee Commander Keen 5 data
CK6	iD/Apogee Commander Keen 6 data
CL	Generic LISP Source code
CL3	Layout file (Adaptec Easy CD Creator)
CLASS	Java class
CLG	Disk Catalog database
CLL	Cricket Software Clicker File
CLO	Cloe Image
CLP	Windows Clipboard
CLP	Quattro Pro Clip art
CLP	Clipper 5 Compiler Script
CLR	1st Reader Binary color screen image
CLR	PhotStyler Color defintion
CLS	Visual Basic Class Module
CLS	C++ Class Definition
CM	Craftman Data
CMA	Database file in plain text format (APPLIX TM1)
CMD	Command file for Windows NT (similar to a DOS .BAT file), OS/2
CMD	DOS CP/M command file
CMD	dBase-II program file
CMD	1st Reader External Command Menu
CMF	Corel Metafile
CFM	Creative FM-Music
CMG	Chessmaster saved game
CMK	Card Shop Plus file
CMM	CEnvi Batch file
CMP	JPEG Bitmap
CMP	Address document
CMP	CorelDRAW 4.0 Postscript Printer Header
CMP	Route 66 Address Document
CMP	Microsoft Word for DOS User dictionary
CMR	MediaPlayer Movie
CMU	Raster image file (Stereo), (developed by Carnegie Mellon University)
CMV	Corel Move animation
CMX	Corel Presentation Exchange image
CMYK	Raw cyan, magenta, yellow, and black bytes file
CNC	CNC General Program data
CNF	Configuration file used by Telnet, Windows, and other applications with varying internal formats
CNM	Windows application menu options and setup file
CNQ	Compuworks Design Shop file
CNT	Windows (or other) system content files for the help index and other purposes
CNV	Word for Windows Data conversion support file
CNV	WordPerfect for Windows Temporary file
CNV	Conversion files (WS_FTP Pro) files that will be converted from (Example) "HTML-"HTM" for upload
COB	trueSpace 2 object
COB	COBOL Source code
COD	Microsoft C compiler output as displayable machine language/assembler with original C as comments
COD	FORTRAN Compiled code
COD	dBase Application Generator Template source file
COD	Video Text file
COL	AutoDesk Animator Color Palette
COL	Microsoft Multiplan Spreadsheet
COM	Command file (program)
CON	Simdir Configuration file
CP8	CP8 256 Gray Scale image
CPD	Corel PrintOffice file (drawing)
CPD	Fax Cover document
CPD	Complaints Desk Script
CPE	Fax Cover document
CPF	The Complete Fax (Fax file)
CPH	Image file (Corel Print House) see CPO
CPI	Microsoft MS-DOS code page information
CPI	ColorLab Processed Image bitmap
CPJ	CeQuadrant CD Project
CPL	Control Panel Module
CPL	Compel Presentation
CPL	Corel color palette
CPO	Image file (Corel Print Office)
CPP	C++ Source code
CPP	CA-Cricket Presents presentation
CPR	Corel Presents presentation
CPS	Central Point PC Tools Backup
CPS	Coloured postscript
CPT	Corel Photo-Paint image
CPT	Macintosh Compressed Archive
CPT	dBase Encrypted Memo
CPT	CA-Cricket Presents Template
CPX	Corel Presentation Exchange compressed drawing
CPY	Data file (Copy Books)
CPZ	COMPOZ Music Text
CRC	Circular reference file (Pro/Engineer)
CRC	Check file (Win-SFV32) (Fantasia Software)
CRD	Microsoft Windows 3.x Cardfile
CRF	Zortech C++ cross-reference
CRH	Image file (Microsoft Golf)
CRP	Corel Presents run-time presentation
CRP	Visual dBASE custom report
CRP	dBase IV Encrypted database
CRS	WordPerfect 5.1 for Windows File Conversion resource
CRT	Certificate file
CRT	Oracle Terminal settings information
CRT	Crontab file)
CRU	CRUSH Compressed archive
CSA	Comma deliminated text
CSC	Corel script
CSG	Statistica/w Graph file
CSH	C shell script files (Hamilton Labs)
CSM	Borland C++ 4.5 Precompiled header
CSM	Script file (Kodak Dc265 Camera)
CSO	Customer service data and outcome file
CSP	PC Emcee On-Screen image
CSS	Stats+ Datafile
CSS	Statistica/w Datasheet
CSS	Cascading Style Sheet (MIME)
CST	Macromedia Director "Cast" (resource) file
CSV	Comma-separated values file
CSV	CompuShow Adjusted EGA/VGA Palette
CT	Scitex CT bitmap
CT	A graphic file associated with the Paint Shop Pro Graphic Editor
CTC	PC Installer Control
CTF	Symphony Character code translation
CTL	Used in general for files containing control information. FAXWorks uses it to keep information about each fax sent and received.
CTL	dBase IV Control
CTX	Visual Basic User control binary file
CTX	Pretty Good Privacy (PGP) Ciphertext file
CTX	Microsoft Online Course Text
CUE	Microsoft Cue Cards data
CUL	Cursor library file (IconForge)
CUR	Windows Cursor
CURSOR	Sun Microsystems Cursor
CUT	Dr Halo Bitmap
CV	Corel Versions archive
CV	Microsoft CodeView information screen
CVG	Image
CVS	Canvas drawing file
CWK	Claris Works data
CWS	Claris Works template
CXT	Macromedia Director protected (not editable) "Cast" (resource) file
CXX	C++ source code
C--	Sphinx C-- Source code
C00	Ventura Publisher Print file
C01	Typhoon wave
C86	Computer Innovation (C86) Source code
 
D
DAO	Windows Registry Backup
DAP	Data access page (Microsoft Access 2000)
DAT	Data file
DAT	A data file extension used to designate an error message in a inbound internet email message (Microsoft Exchange Server v 5.0) 
DAT	WordPerfect Merge Data
DAT	Extension used for some MPEG files
DB	Borderland's Paradox 7 table database
DBC	Microsoft's Visual FoxPro database container file
DBF	A dBASE file, a format originated by Ashton-Tate, but understood by Act!, Clipper,FoxPro, Arago, Wordtech, xBase, and similar database or database-related products. 
DBF	Enable database (can be opened with Excel 97)
DBF	Oracle 8.1.x tablespace file
DBK	dBase Database Backup
DBK	Schematic backup file (Orcad Schematic Capture)
DBO	Compiled program file (dBase IV)
DBQ	Paradox Memo
DBT	dBase Text Memo
DBV	Memo field file (Flexfile 2)
DBW	Microsoft Windows 9.x Database file (DataBoss)
DBX	DataBeam image
DBX	Microsoft's Visual Foxpro Table file
DC	CAD file (DesignCAD)
DC2	CAD file (DesignCAD)
DCA	Document Content Architecture Text file (IBM DisplayWrite)
DCA	Visual Basic Active designer cache
DCD	Document content description file (used in XML)
DCF	Disk Image file
DCF	Data file (Dyadic)
DCIM	Digital Imaging and Communications in Medicine (image and data)
DCM	DCM module
DCP	Data CodePage (OS/2)
DCR	Shockwave file
DCS	Desktop Color Separation file
DCS	Bitmap Graphics (Quark XPress)
DCS	Datafile (ACT! Activity file)
DCT	Microsoft's Visual FoxPro database container file
DCT	Database Dictionary file (Clarion Database Developer)
DCT	Database SpellCheck Dictionary (Harvard Graphics 3.0-Symphony)
DCU	Delphi compiled unit
DCX	Microsoft's Visual FoxPro database container file
DCX	Fax image (based on PCX)
DCX	Macro file
DCX	Bitmap Graphics file (Multipage PCX)
DC5	DataCAD Drawing
DD	Compressed Archive (Macintosh DISKDOUBLER)
DDB	Bitmap Graphics file
DDF	Btrieve or Xtrieve Data Definition File, which contains metadata describing a Btrieve or Xtrieve file
DDI	Image File (DISKDUPE)
DDIF	Digital Equipment or Compaq file. Used for storing images and their word processing documents
DDP	Device Driver Profile (OS/2)
DEB	Debug Script (DOS Debug)
DEF	SmartWare II data
DEF	Define Module file (3-D Fassade Plus)
DEF	C++ definition file
DEF	Assembly Header file (Geoworks)
DEFI	Oracle 7 de-install script
DEI	Design Engineered Interface (GSI), Gerber Systems Inc.)
DEM	Demo file (Descent)
DEM	A file with USGS standards for Digital Elevation Models (Vista Pro)
DEM	Graphics file (Vista Pro)
DEP	Visual Basic Setup Wizard Dependency file
DER	Certificate file
DEV	Device Driver
DEWF	Macintosh SoundCap/SoundEdit recorded instrument file
DEZ	Encrypted zip file (DES Encryption)
DFD	Data Flow Diagram Graphic (Prosa)
DFI	Outline Font description (Digifont)
DFL	Default Program Settings (Signature)
DFM	Data Flow Diagram model (Prosa)
DFS	Sound File (Delight)
DFV	Printing Form value (Microsoft Word)
DGN	Microstation95 CAD drawing
DGS	Diagnostics Report
DH	Dependency Information file (Geoworks)
DHP	Graphic file (Dr. Halo II-III PIC Format)
DHT	Datafile (Gauss)
DIA	Diagraph Graphics file (Computer Support Corporation)
DIB	Device-independent bitmap
DIC	Dictionary file
DIC	Dictionary file (Lotus Notes, Domino)
DICM	Digital imaging and communications in medicine file (DICOM)
DIF	Data Interchange Format spreadsheet
DIF	Database file (VisiCalc)
DIF	Data Interchange Output file
DIF	Text file (Output from Data Interchange Format)
DIG	Digilink file
DIG	Sound Designer I audio
DIP	Graphics file
DIR	Macromedia Director file
DIR	Dialing Directory (ProComm Plus)
DIR	Directory (VAX) (DEC)
DIR	Movie (MacroMind Director 4.x)
DIS	Ray Tracer file
DIS	Distribution file (VAX Mail)
DIS	Thesaurus file (CorelDraw)
DIT	Active directory schema (Microsoft Windows 2000)
DIZ	Description file (Description in ZIP)
DKB	Graphics file (Ray Traced DKBTrace)
DL	Image
DLD	Datafile (Lotus 1-2-3)
DLG	C++ Dialogue Script
dll.htmDLL	Dynamic-link library file
DLL	Export/Import Filter (CorelDraw)
DLS	Downloadable sound
DLS	Interactive music architecture (IMA)(Microsoft),(Blood2)
DLS	Setup file (Norton DiskLock)
DMD	Visual dBASE data module
DMF	Packed Amiga disk image
DMF	X-Trakker music module (MOD)
DMO	Demo file (Derive)
DMP	Dump file (Screen or Memory)
DMS	Compressed Archive (Amiga DISKMASHER)
DOB	Visual Basic User document
DOC	FrameMaker or FrameBuilder document
DOC	WordStar document
DOC	WordPerfect document
DOC	Microsoft Word document
DOC	DisplayWrite document
DOC	Document format (Interleaf)
DOG	Screen Saver file (Laughing Dog Screen Saver)
DOH	Dependency Information file (Geoworks)
DOS	External Command file (1st Reader)
DOS	Network Driver file (PKT_DIS.dos)
DOS	Text file (DOS)
DOT	Word Document Template (Microsoft Word for Windows)
DOT	Line-Type definition (CorelDraw)
DOX	User document binary form (Visual Basic)
DOX	Text file (MultiMate 4.x)
DOZ	Description out of Zip (VENDINFO)
DP	Calendar file (Daily Planner)
DP	Datafile (DataPhile)
DPJ	DeskProto project file (DeskProto CAM)
DPL	Borland Delphi 3 packed library
DPR	Project header (Borland C++)
DPT	Publication file (Publish-It!)
DRAW	Acorn's object-based vector image
DRC	Design rules check report file (Orcad Schematic Capture)
DRS	Display Resource file (Microsoft WordPerfect for Windows)
DRV	Driver
DRV	Device Driver (Required to make a device function)
DRW	Vector graphics (Micrografx)
DRW	Lotus Freelance Image
DRW	Pro/E drawing
DS4	Micrografx Designer Image
DR9	Directory file
DS4	Vector Graphics (Micrografx)
DSC	Discard file (Oracle)
DSD	Database file (DataShaper)
DSD	Document structure definition file (Used in XML)
DSF	Micrografx Designer v7.x file
DSG	DooM saved game
DSK	Project Desktop file (Borland C++/Turbo Pascal)
DSK	Driver file (Novell Netware)
DSM	Dynamic Studio music module (MOD)
DSM	Digital Sound Module (DSI)
DSM	Music module file (DSIK)
DSN	ODBC Data source
DSN	Design (Object System Designer)
DSN	Schematic file (Orcad Schematic Capture)
DSP	Microsoft Developer Studio project
DSP	Display parameters (Signature)
DSP	Graphics Display driver (Dr. Halo)
DSQ	Corel QUERY
DSR	Visual Basic Active designer file
DSR	Driver Resource (Microsoft WordPerfect for Windows)
DSS	Screensaver file (DCC)
DSS	Digital Sound file (Digital Soup))
DST	Embroidery machines graphic file
DST	Distribution file (PC-RDist, by Pyzzo)
DSW	Desktop settings (Borland C++ 4.5)
DSW	Microsoft Developer Studio workspace file
DSX	Visual Basic Active designer binary file
DT_	Data file fork (Macintosh)
DTA	World Bank's STARS data
DTA	Datafile (Turbo C++)
DTD	SGML Document Type Definition (DTD) file
DTED	Digital terrain elevation data (geographic data format)
DTF	Database file (PFS-Questions & Answers)
DTF	Symantec Q&A relational database
DTM	Module file (DigiTrakker)
DTP	Desktop layout file (SecurDesk!/SecurDesk! LV)
DTP	Text Document (Timeworks Publisher 3.x)
DTP	Template file (Pressworks)
DUN	Microsoft Dial-up Networking Export file
DUP	Duplicate Backup
DV	Digital video (MIME)
DVC	Datafile (Lotus 1-2-3)
DVF	Graphics file associated with camcorders (DV Studio)
DVI	Binary file (TeX)
DVI	Device Independent Document (TeX) (LaTeX)
DVP	Desqview Program information (DESQview)
DVP	Device parameter file (AutoCAD)
DW2	Drawing file (DesignCAD for Windows)
DWC	Compressed Archive (DWC)
DWD	DiamondWare digitized file
DWF	Vector graphic (Autodesk)
DWF	CAD drawing in Vector Graphics format
DWF	Drawing Web file (Microsoft WHIP autoCAD reader)
DWG	AutoCAD Drawing 
DWG	AutoCAD drawing, or older Generic CAD drawing file
DWP	Document file (DeScribe)
DWS	Workspace file (Dyadic)
DWT	Template file, or prototype (AutoCAD)
DX	Digital Electric Corporation (DEC) Data exchange file
DXF	Drawing Interchange (eXchange) format,a text representation of the binary DWG format
DXF	Drawing Interchange Format (AutoCAD)
DXF	Data Exchange File
DXN	Fax document (Fujitsu dexNet)
DXR	Macromedia Director protected (not editable) movie file
DYN	Datafile (Lotus 1-2-3)
D2D	2D/3D object file (3-D Fassade Plus)
D64	Commodore 64 emulator disk image	
 
E
e00	Exchange file (Arc/Info)
EBJ	Error Checking Object file (Geoworks)
ED5	EDMICS image
ED6	EDMICS image
EDA	Ensoniq ASR disk image
EDB	ROOTS3 Geneological data file
EDE	Ensoniq EPS disk image
EDD	Element Definition document (FrameMaker+SGML documents)
EDK	Ensoniq KT disk image
EDQ	Ensoniq SQ1/SQ2/KS32 disk image
EDS	Ensoniq SQ80 disk image
EDT	Default settings (VAX Edt editor)
EDV	Ensoniq VFX-SD disk image
EEB	Button Bar for Equation editor (Microsoft WordPerfect for Windows)
EFA	Ensoniq ASR file
EFE	Ensoniq EPS file
EFK	Ensoniq KT file
EFQ	Ensoniq SQ1/SQ2/KS32 file
EFS	Ensoniq SQ80 file
EFT	High Resolution Screen Font (ChiWriter)
EFV	Ensoniq VFX-SD file
EFX	Fax Document (Everex EFax)
EFX	Fax document (Efax Reader)
EGA	EGA Display font (Ventura Publisher)
EKM	Keyboard macro definitions file (EXP: The Scientific Word Processor)
EL	Lisp Source code (eMacs)
ELC	eMac Lisp Source code (byte-compiled)
ELM	Theme-Pack file for (Microsoft FrontPage)
ELT	Event List Text file (Prosa)
EMB	Embedded bank File (Everest)
EMD	ABT Extended MoDule
EMF	Enhanced Windows Metafile
EML	Microsoft Outlook Express mail message (MIME RFC 822)
EMS	Enhanced Menu System Configuration file (PC Tools)
EMU	Terminal Emulation Data file (BITCOM)
ENC	Music file (Encore)
ENC	Video file
ENC	Encoded file (UUENCODEd File, Lotus 1-2-3)
END	Arrow-Head Definition Table (CorelDraw)
ENFF	Neutral Format
ENG	Dictionary Engine file (Sprint)
ENG	Chart Graphics file (EnerGraphics)
ENV	Enveloper Macro (WOPR)
ENV	Environment file (Microsoft WordPerfect for Windows)
EPD	Publication file (Express Publisher)
EPHTML	Enhanced Perl-parsed HTML
EPI	Document file (Express Publisher)
EPS	Encapsulated Postscript Vector graphics (Adobe Illustrator)
EPS	Printer font (Epson, Xerox, Ventura Publisher)
EPS2	Adobe Level II Encapsulated Postscript
EPS	Encapsulated PostScript image file
EPSF	Encapsulated PostScript
EPSI	Adobe Encapsulated Postscript Interchange
EQN	Equation file (Microsoft WordPerfect for Windows)
ER1	ERWin file
ERD	Entity Relationship Diagram graphic file (Prosa)
ERM	Entity Relationship Diagram Model file (Prosa)
ERR	Stores the error messages that result when the RoboHELP Help Compiler attempts to compile the source files of a Help system
ERR	Compilation error file (Microsoft Visual FoxPro)
ERX	ERWin file
ESF	Audio file (Emblaze)
ESH	Extended Shell Batch file (DOS)
ESL	Distributable support library file (Microsoft Visual FoxPro)
ESPS	ESPS audio file
ESS	Style sheet (EXP: The Scientific Word Processor)
ETH	Document file (Ethnograph 3.x)
ETX	Structure Enhanced text (SetText)
EUI	Ensoniq ESP family compacted disk image
EVT	Event Log (Microsoft Windows NT, 2000)
EVY	Document (Microsoft Wordperfect for Windows Envoy)
EWD	Text Document (Express Publisher for Windows)
EWL	Microsoft Encarta document
EXT2	Second extended file system (Linux)
EXT3	Third extended file system (Linux)
EX3	Device Driver file (Harvard Graphics 3.x)
EXC	Microsoft Word Exclusion Dictionary file
EXC	Source Code file (Rexx VM/CMS)
EXC	Exclude file for Optimize (do not process, QEMM)
EXE	Executable file (program)
EXP	Saved chat (ICQ)
EXT	ASCII binary transfer file (WS_FTP PRO) (IPSWITCH Software)
EZP	Compressed file (Edify.zip) (Edify Electronic Workforce Backup Utility)
E00	Coverage export file (ArcInfo)

F
F	FORTRAN file
F	Compressed file archive (FREEZE)
FAC	Face graphic
FAQ	Frequently Asked Questions document
FAR	Music module (MOD) (Farandole Composer)
FAS	Basic module file (3-D Fassade Plus)
FAV	Navigation bar (Microsoft Outlook)
FAX	FAX Type image
FBK	Backup (Navison Financials)
FC	Spell Check dictionary file (Harvard Graphics)
FCD	Virtual CD-ROM file
FCD	Output file (FastCAD/EasyCAD)
FCM	Binary file patch (Forward Compression)
FD	Declaration file (FORTRAN)
FD	Field offsets for compiler (DataFlex)
FDB	Database (Navison Financials)
FDF	Forms Document (Adobe Acrobat)
FDW	Document form (F3 Design and Mapping)
FEB	Button Bar for Figure Editor (Microsoft WordPerfect for Windows)
FEM	CADRE Finite Element Mesh
FF	Outline Font description (AGFA CompuGraphics)
FFA	MS find fast file
FFF	Fax document (defFax)
FFF	GUS PnP bank file
FFL	MS fast find file
FFL	Image file (PrintMaster Gold)
FFO	MS fast find file
FFT	Final Form Text (part of IBM's DCA)
FFX	MS fast find file
FH3	Aldus Freehand 3 drawing (Vector graphic)
FH4	Aldus Freehand 4 drawing (Vector graphic)
FI	File Interface (FORTRAN)
FIF	Fractal Image
FIG	REND386/AVRIL file
FIL	File template (Application Generator)
FIL	File List Object (dBase Application Generator)
FIL	Overlay (Microsoft WordPerfect for Windows)
FIN	Print formatted text (Perfect Writer)
FIT	Graphic (FITS)
FIT	File index table (Microsoft Windows NT)
FITS	CCD camera image
FITS	Flexible Image Transport System file
FIX	Patch file (Generic)
FKY	Macro (Microsoft FoxPro)
FLA	Movie (Macromedia Flash)
FLB	Format library (Papyrus)
FLC	FLIC animation (AutoDesk)
FLD	File folder (Charisma)
FLD	Field define module file (3-D Fassade Plus)
FLF	Delived form (Corel Paradox)
FLF	License (Navison Financials)
FLI	FLIC animation (AutoDesk)
FLI	Font library (EmTeX)
FLF	Driver (OS/2)
FLL	Distributable dynamic link library (DLL) (Microsoft Visual FoxPro)
FLM	Film Roll (AutoCAD)
FLO	FlowCharter file (MicroGrafx)
FLS	Filelist document (Farrukh Imposition Publisher)
FLT	Graphics filter (Microsoft)
FLT	Filter (Corel)
FLT	Filter (Micrografx Picture Publisher)
FLT	Graphics filter support file (Asymetrix ToolBook)
FLT	Music module (MOD) (StarTrekker)
FLT	Open Flight file (MulitGen)
FLX	Compiled binary file (DataFlex)
FM	Spreadsheet (FileMaker Pro)
FM	FrameMaker Document (Adobe)
FM1	Spreadsheet (Lotus 1-2-3, version 2.x)
FM3	Device driver (Harvard Graphics, version 3.0)
FM3	Spreadsheet (Lotus 1-2-3, version 3.x)
FMB	Binary source code for form, (Oracle, v4.x and later)
FMB	File Manager button bar (Microsoft WordPerfect for Windows)
FMF	Font or Icon (IBM LinkWay)
FMK	MakeFile (FORTRAN PowerStation)
FML	Mirror list (Oracle)
FMO	Compiled format (dBase IV)
FMP	Document file (FileMaker Pro)
FMT	Text format for form file (Oracle, v4.x and later)
FMT	Print file (Microsoft Schedule+)
FMT	Style sheet (Sprint)
FMT	Csreen format file (Microsoft Visual FoxPro)
FMX	Executable form, (Oracle,v4.x and later)
FN3	Font (Harvard Graphics)
FND	Saved Search (Find applet) (Microsoft Explorer)
FNG	Font group (Font Navigator)
FNK	Module (FunkTracker)
FNT	Font (Generic)
FNX	Inactive font (Exact)
FO1	Font (Borland Turbo C)
FO2	Font (Borland Turbo C)
FOG	Fontographer font
FOL	Saved message folder (1st Reader)
FON	Font (Generic)
FON	Call log (Procomm Plus)
FON	System font (Generic)
FON	Dialing directory (Telix)
FOR	FORTRAN source code
FOR	Form (WindowBase)
FOT	Font-related file (Generic)
FOT	Installed TrueType font (Microsoft Windows Font Installer)
FP	Configuration file (FoxPro)
FP	FileMaker Pro file
FP1	"Flying Pigs" screensaver datafile (Microsoft Windows 9.x)
FP3	FileMaker Pro v.3 & 4 document file
FP5	Document file (FileMaker Pro v.5)
FPC	Catalog file (FoxPro)
FPT	FileMaker Pro file
FPT	Memo fields (Microsoft FoxPro)
FPW	Floorplan drawing (FloorPlan Plus for Windows)
FPX	Bitmap (FlashPix)
FR3	Renamed dBaseIII+ form (dBase IV)
FRF	Font (FontMonger)
FRG	Uncompiled report (dBase IV)
FRK	Zip (compressed ) file (Macintosh)
FRM	Form (Generic)
FRM	Document (FrameMaker or FrameBuilder)
FRM	Executable file (Oracle,v3.0 and earlier)
FRM	Form (Visual Basic)
FRM	Merge form (Microsoft WordPerfect for Windows)
FRM	Symbol Report (DataCAD)
FRO	Compiled report (dBase IV)
FRP	Form (PerForm PRO Plus)
FRS	Screen Font Resource (Microsoft Wordperfect for Windows)
FRT	Report menu (FoxPro)
FRX	Form stash file (Visual Basic)
FRX	Report (Microsoft FoxPro)
FSF	fPrint Audit Tool
FSL	Paradox 7 form (Borderland) 
FSL	Form (Paradox for Windows)
FSL	Saved form (Corel Paradox)
FSM	Sample file (Farandoyle)
FST	Linkable program (dBFast)
FSX	Data (Lotus 1-2-3)
FT	Full text index (Lotus Notes)
FTB	Index file (Roots3)
FTF	Client access data specification file (AS/400) (Client to Server)
FTG	Help system full-text search group file (Microsoft Windows)
FTM	Font (MicroGrafx)
FTP	File transfer protocol (Internet Generic)
FTS	Help system full-text search index (Windows)	
FTW	Document file (Family Tree Maker)	
FW	Database (Framework II)	
FW2	Database (Framework II)	
FW3	Database (Framework III)	
FW4	Database (Framework IV)	
FWB	Data file backup for file splitting configuration (FileWrangler)	
FWS	Data file for file splitting configuration (FileWrangler)	
FX	On-Line guide (FastLynx)	
FXD	Phonebook (FAXit)	
FXP	Compiled source code (FoxPro)	
FXS	Fax Transmit graphic (WinFax)	
FZB	Bank dump file (Casio FZ-1)	
FZF	Full dump file (Casio FZ-1)	
FZV	Voice dump file (Casio FZ-1)	
F01	Fax document (Perfect Fax)	
F06	Dos screen text font (height= 6 pixels)	
F07	Dos screen text font (height= 7 pixels)	
F08	Dos screen text font (height= 8 pixels)	
F09	Dos screen text font (height= 9 pixels)	
F10	Dos screen text font (height= 10 pixels)	
F11	Dos screen text font (height= 11 pixels)	
F12	Dos screen text font (height= 12 pixels)	
F13	Dos screen text font (height= 13 pixels)	
F14	Dos screen text font (height= 14 pixels)	
F15	Dos screen text font (height= 15 pixels)	
F16	Dos screen text font (height= 16 pixels)	
F2R	Linear music module (Farandole)	
F3R	Blocked music module (Farandole)	
F77	Source code file (FORTRAN 77)	
F90	FORTRAN file	
F96	Fax document (Frecom FAX96)	

G
G	Data chart (APPLAUSE)
GAL	Album (Corel Multimedia Manager)
GAM	Fax document (GammaFax)
GB	Emulator ROM image file (Nintendo GameBoy)
GBC	Color emulator ROM image file (Nintendo GameBoy)
GBL	Global definitions (VAXTPU Editor)
GC1	Lisp source code (Golden Common Lisp 1.1)
GC3	Lisp source code (Golden Common Lisp 1.1)
GCD	Generic (TM) CADD drawing (later versions)
GCP	Image processing file (Ground Control Point)
GDB	Database file (InterBase)
GDF	Dictionary file (GEOS)
GDM	Bells, whistles, and sound boards module
GED	Genealogical data (GEDCOM)
GED	Graphic Environment Document (drawing)
GED	Graphics editor native format (Arts & Letters)
GED	Graphics editor file (EnerGraphics)
GEM	Metafile (GEM)
GEM	Vector graphics (Ventura Publisher)
GEN	Generated text (Ventura Publisher)
GEN	Compiled template (dBase Application Generator)
GEO	Geode (Geoworks)
GetRight	Unfinished-Download (GetRight)
GFB	Compressed gif image (GIFBLAST)
GFC	Patton&Patton Flowcharting 4 flowchart
GFI	Graphics Link presentation (Genigraphics)
GFT	Font (NeoPaint)
GFX	Genigraphics Graphics Link presentation
GIB	Chart (Graph-in-the-Box)
GID	Windows 95 global index (containing help status)
GIF	Bitmap (CompuServe)
GIM	Graphics Link presentation (Genigraphics)
GIW	Presentation (Graph-in-the-Box for Windows)
GIX	Graphics Link presentation (Genigraphics)
GKH	Ensoniq EPS family disk image
GKS	GripKey document (Gravis)
GL	Animation file (GRASP graphical System for Presentation)
GLM	Datafile (Glim)
GLS	Datafile (Across)
GLY	Glossary (Microsoft Word)
GMF	CGM Graphics (APPLAUSE)
GMP	Tile map (Geomorph) (SPX)
GMR	Graphical monitor record (Schlafhorst Automation)
GNA	Graphics Link presentation (Genigraphics)
GNO	Genealogy document file (Genopro)
GNT	Generated executable code (Micro Focus)
GNX	Graphics Link presentation (Genigraphics)
GOC	Goc sorce code (Geoworks)
GOH	Goc header (Geoworks)
GP	Geode parameter file (Geoworks Glue)
GPH	Graph (Lotus 1-2-3/G)
GPK	Program package (Omnigo)
GPP	Graph paper application file (GraphPap) (Generates graph paper)
GR2	Screen driver (Microsoft Windows 3.x)
GRA	Graph (Microsoft)
GRA	Datafile (SigmaPlot)
GRB	Shell Monitor (MS-DOS v5.0)
GRD	Image processing grid (CHIPS)
GRF	Grapher (Golden Software) graph
GRF	Graph (Charisma Graph Plus)
GRP	Program Manager Group (Microsoft)
GRP	Pictures group (PixBase)
GRY	Raw graphic (GREY)
GS1	Presentation (GraphShow)
GSD	Vector graphic (Professional Draw)
GSM	Audio stream Raw GSM (6.10 audio stream)
GSM	Audio stream Raw 'byte aligned (GSM 6.10 audio stream)
GSM	GSM w.o. header/VoiceGuide/RapidComm file (US Robotics voice modems)
GSM	GSM w. header/QuickLink file (US Robotics voice modems)
GSP	Sketch pad file (GeoMeter Sketch Pad)
GSP	Zip file (Gnuzip) (Allows for output to html)
GSW	Worksheet (GraphShow)
GTK	Music module (Graoumftracker) (old) (MOD)
GT2	Music module (Graoumftracker) (new) (MOD)
GUP	Data (PopMail)
GWP	Greetings WorkShop file
GWX	Graphics Link presentation (Genigraphics)
GWZ	Graphics Link presentation (Genigraphics)
GXL	Graphics library (Genus)
GZ	Compressed file (Unix gzip)
G721	Raw CCITT G.721 $bit ADPCM data
G723	Raw CCITT G.723 3 or 5bit ADPCM data
G8	Raw Graphics (one byte per pixel) Plane III (PicLab)

H
H	Program header (C)
HA	Compressed archive (HA)
HAL	Hal add-on file (Lotus 1-2-3)
HAM	Driver file (Novell Netware)
HAM	Vector graphics saved file (Amiga)
HAP	Compressed archive (HA)
HBK	Handbook (MathCad)
HBK	Accounting data file (Humanic Software)
HCM	Configuration file (IBM HCM)
HCOM	Sound Tools file (HCOM)
HCR	Production configuration file (IBM HCD/HCM)
HDA	Document file (HotDocs)
HDF	National Center for Supercomputing Applications (NCSA) Geospatial Hierarchical Data format
HDF	Help file (Help development kit)
HDF	Hierarchical data file
HDL	Alternate download listing (ProComm Plus)
HDR	Database header (Pc-File+)
HDR	Datafile (Egret)
HDR	Message header text (ProComm Plus)
HDR	Message header text (1st Reader)
HDW	Vector graphics (Harvard Draw)
HDX	Help index (AutoCAD)
HDX	Help index (Zortech C++)
HED	Document (HighEdit)
HEL	Hellbender saved game (Microsoft)
HEX	Macintosh BinHex 2.0 file
HFI	HP font info (GEM)
HFX	Data file (US Robotics Rapid Comm Voice)
HGL	Drawing file (HP Graphics Language)
HH	Help system map (Generic)
HH	Header file (C++)
HHH	Precompiled header (Power C)
HHP	Help information for remote users (ProComm Plus)
HIT	Audio file (HitPlayer)
HLB	Help library (VAX)
HLP	Help file (Generic)
HLP	Windows Help file (DataCAD)
HMI	Human machine interfaces MIDI music file (Descent)
HMM	Alternate mail read option menu (ProComm Plus)
HMP	Human machine interfaces MIDI music file (Descent)
HMP	Database file (InfoMgr)
HNC	Program files (CNC)
HOG	Lucas Arts Dark Forces WAD file
HOG	Mission file (Descent 1-2)
HOG	Main data package file (Descent3)
HOT	Document file (HotSend)
HP8	Ascii text Roman8 character set (NewWave Write)
HPC	Font language file (Hewlett-Packard)
HPF	HP LaserJet font (Adobe Pagemaker)
HPF	Partial download file (HotLine)
HPG	HPGL Plotter vector graphics (AutoCAD)
HPG	HPGL Plotter vector graphics (Harvard Graphics)
HPI	Font information (GEM)
HPJ	Help Project file (Visual Basic)
HPK	Compressed archive (HPACK)
HPM	Emm text (HP NewWave)
HPM	Alternative menu for privileged users (ProComm Plus)
HPP	Program header (C++) 
HPP	Database file (InfoMgr)
HPP	Header file (Zortech C++)
HQX	BinHex (Macintosh 4.0)
HRF	Rastor graphic (Hitachi)
HRM	Alternate menu for limited users (ProComm Plus)
HS2	Monochrome image (Postering)
HSC	FM synthesized music file (Used by many old games, e.g.:FINTRIS, ROL)
HSI	Graphic (Handmade Software, Inc.)
HST	History file (Generic)
HST	History file (ProComm Plus)
HT	HyperTerminal file
HTA	A HTML file that has been used to by viruses to update the system registry
HTM	A Web page (a file containing Hypertext Markup Language - HTML - markup)
HTML	A Web page (a file containing Hypertext Markup Language - HTML - markup)
HTT	Hypertext template (Microsoft)
HTX	Template (Extended HTML)
HWD	Presentation (Hollywood)
HWP	Korean word processor document format (HanGul)
HXM	HAM extension (Descent2)
HXM	Alternate protocal selection menu (ProComm Plus)
HXX	Header file (C++)
HY1	Hyphenation algorythm (Ventura Publisher)
HY2	Hyphenation algorythm (Ventura Publisher)
HYC	Datafile (Microsoft WordPerfect for Windows)
HYD	Hyphenation dictionary (Microsoft WordPerfect for Windows)
HYM	3D Image binary file (Hymarc Scandata Scanner)
HYP	Compressed archive (HYPER)
H!	On-line Help (Flambeaux Help!)
H++	Header file (C++)
H--	Header file (Sphinx C--)

I
I	Intermediate file (Borland C++)
IAN	Text file (Sterling Software) (Groundworks COOL Business Team Model)
IAX	Bitmap (IBM Image Acess eXecutive)
IBM	Compressed archive (ARCHDOS, IBM Internal only)
ICA	Citrix file
ICA	Bitmap graphic (Image Object Content Architecture)
ICB	Targa bitmap
ICC	Printer file (Kodak)
ICC	Catalog file (IronClad)
ICD	Drawing file (IronClad)
ICL	Icon Library (Generic industry standard)
ICM	Image Color Matching profile
ICN	Icon source code
ICO	Icon (Microsoft Windows 3.x)
ICS	Scene file (IronClad)
ID	Disk identification file (Generic)
IDB	Intermediate file (Microsoft Developer)
IDD	MIDI Instrument Definition
IDE	Project file (Borland C++ v4.5)
IDF	MIDI Instrument Definition (Windows 95 required file)
IDIF	Identification file (Netscape saved address book)
IDQ	Data Query (Internet)
IDW	Vector graphic (IntelliDraw)
IDX	Relational database index (Microsoft FoxPro)
IDX	Relational database index (Symantec Q&A)
IDX	Microsoft Outlook Express file
IDX	Index file (Microsoft Clip Gallery v. 1.x)
IDX	Index file (Pro/Engineer)
IFD	Form (JetForm Design)
IFF	Interchange File Format,(data storage format)(Amiga,Electronic Arts)
IFF	Image (Sun TAAC/SDSC Image Tool)
IFO	Digital Video Disk (DVD) datafile
IFO	Graphic object layer data (ImageForge Pro)
IFP	Script file (KnowledgeMan)
IFS	Compressed fractal image (Yuvpak)
IFS	System file (OS/2)
IFS	Create executable library (ImageForge/ImageForge Pro)
IGES	Initial Graphics Exchange Specification (Generic)
IGF	Metafile (Inset Systems)
IGR	Drawing design file (SmartSketch, by InterGraph)
IIF	Interchange file (QuickBooks for Windows)
IIM	Music module
ILB	Datafile (Scream Tracker)
ILBM	Bitmap (graphic image)
ILK	Program outline (Microsoft ILink incremental linker)
IM8	Raster graphic (Sun Microsystems)
IMA	Image (WinImage)
IMA	Vector graphic (EGO,Chart)
IMF	MIDI music file (Corridor 7, Blake Stone, Wolfenstein 3D, Spear of Destiny)
IMG	Image (GEM)
IMG	Bitmap graphic (Ventura Publisher)
IMP	Spreadsheet (Lotus Improv)
IMQ	Image presentation (ImageQ)
IMS	Create executable library data (IconForge)
IN$	Installation file (HP NewWave)
IN3	Input device driver (Harvard Graphics v3.0)
INB	Test script (Vermont High Test)
INC	Include file (Assembler language or Active Server)
IND	Index (dBase IV)
IND	Shared Database file (Specifically in Microsoft Windows)
INF	Information file (Generic)
INF	Type I LaserJet font information file
INF	Install script (Generic)
INI	Initialization file (Generic)
INI	Setup file (MWave DSP synth's mwsynth.ini GM)
INI	Bank setup file (Gravis UltraSound)
INK	Pantone reference fills file (CorelDRAW)
INL	Inline function file (Microsoft Visual C++)
INP	Source code for form, (Oracle,version 3.0 and earlier)
INRS	INRS-Telecommunications audio
INS	Install script (InstallShield)
INS	Sign-up file (X-Internet)
INS	Instrument file (Ensoniq EPS Family)
INS	Sample (Cell/II MAC/PC instruments)
INS	Datafile (Microsoft WordPerfect for Windows)
INS	Installation script (1st Reader)
INS	Instrument music file (Adlib)
INT	Intermediate executable code (Produced when a source program is syntax-checked)
INT	Interfaced units (Borland)
INX	Index file (Foxbase)
IO	Compressed archive (CPIO)
IOB	3D graphics database (TDDD format)
IOC	Organizational chart (Instant ORGcharting!)
IOF	Findit document (Microsoft Findit)
ION	File description (4dos descript.ion)
ION	Plain text (ASCII Mascot data file), (Matrox)
IPL	Pantone Spot reference pallette (CorelDRAW)
IPS	International patching system binary patch file
IQY	Internet inquiry (Microsoft)
ISO	Lists the files on a CD-ROM; based on the ISO 9660 CD-ROM file system standard
IRS	Resource file (Microsoft WordPerfect for Windows)
ISD	Spell checker dictionary (RapidFile)
ISH	Compressed archive (ISH)
ISO	ISO (International Standards Organization table, aka: ISO)
ISP	Sign-up file(X-Internet)
IST	Instrument file (Digitaltracker)
ISU	Uninstall script (InstallShield)
IT	Settings file (intalk)
ITF	Interface file (JPI Pascal TopSpeed)
IT	Music module (MOD) (Impulse Tracker)
ITI	Instrument file (Impulse Tracker)
ITS	Sample file (Impulse Tracker)
ITS	Internet document set (possibly a Microsoft file)
IV	Open Inventor file
IVD	Microdata dimension or variable-level file (Beyond 20/20)
IVP	User subset profile (Beyond 20/20)
IVT	Table or aggregate data (Beyond 20/20)
IVX	Microdata directory (Beyond 20/20)
IW	Screensaver (Idlewild)
IW	Presentation flowchart (IconAuthor-HSC Interactive)
IWA	Text file (IBM Writing Assistant)
IWC	Install Watch document
IWM	Start file (IconAuthor)
IWP	Text file (Wang)
IXF	Fax document file (IFX for FAX)
IZT	Binary token file (IZT)

J
JAR	Java ARchive (a compressed file for applets and related files)
JAS	Graphic (Generic)
JAVA	Source code (Java)
JBD	Datafile (SigmaScan)
JBF	Image browser file (Paint Shop Pro)
JBX	Project file (Project Scheduler 4.0)
JFF	JPEG image
JIF	JPEG image
JFIF	JPEG image
JMP	Discovery chart-to-statistics (SAS JMP)
JMS	Graphical representation of a Interactive Voice Response call flow (Voxtron TeleButler)
JN1	Jill of the Jungle data (Epic MegaGames)
JNB	Workbook file (Sigma Plot 5)
JOB	Vector graphics file created by conversion of a IMG file (QuestVision)
JOR	Journal (Microsoft SQL Server)
JOU	Journal backup (VAX Edt editor)
JPC	Graphic (Japan PIC)
JPE	JPEG image
JPEG	JPEG compressed bitmap
JPG	JPEG bitmap
JS	JavaScript source code
JSD	Jet Suite document (eFAX)
JSP	A HTML page containing a reference to a Java servlet
JTF	JPEG bitmap
JTF	Fax document (Hayes JT Fax)
JTF	Bitmap graphic (JPEG Tagged Interchange Format)
JTK	Java ToolKit file (Sun Microsystems)
JW	Text document (JustWrite)
JWL	Library (JustWrite)
JZZ	Spreadsheet (Jazz)
J62	Ricoh camera file


K
K25	Sample file (Kurzweil 2500)
KAR	MIDI file (text+MIDI) (Karaoke)
KB	Keyboard script (Borland C++ 4.5)
KB	Program source code (Knowledge Pro)
KBD	Keyboard mapping script (Procomm Plus, LocoScript, Signature)
KBM	Keyboard mapping script (Reflection 4.0)
KCL	Lisp source code (Kyoto Common Lisp)
KDC	Image (Kodak Photo-Enhancer)
KEX	Macro (KEDIT)
KEY	Icon toolbar (DataCAD)
KEY	Datafile (Forecast Pro)
KEY	Keyboard Macro
KEY	Security file (Such as a software registration number)
KFX	Image (KoFax Group 4)
KIZ	Digital postcard (Kodak)
KKW	Contains all K-keywords in the RoboHELP Help project Index Designer not associated with topics
KMP	KeyMaP (Korg Trinity)
KPP	Toolpad (SmartPad)
KPS	Bitmap graphic (IBM KIPS)
KQP	Native Camera file (Konica)
KR1	Sample (multi-floppy) file (Kurzweil 2000)
KRZ	Sample file (Kurzweil 2000)
KSF	Sample File (Korg Trinity)
KYB	Keyboard mapping (FTP)
KYE	Game data (Kye)
 
L
L	Source code (Lex)
L	Source code (Lisp)
L	Linker directive file (WATCOM wlink)
LAB	Datafile (NCSS-SOLO)
LAB	Label file (Visual dBase)
LAB	Mailing labels (Microsoft Excel)
LAN	Loadable module (LAN DLL) (NetWare)
LAY	Word Chart layout (APPLAUSE)
LAY	Clipart file (Printmaster Gold)
LBG	Label generator data (dBase IV)
LBL	Label (dBase IV)
LBL	Label (Clipper 5)
LBL	Label (dBFast)
LBM	Bitmap (DeluxePaint)
LBM	Linear Bitmap graphics (XLib)
LBO	Compiled label (dBase IV)
LBR	Compressed archive (LU)
LBR	Display driver (Lotus 1-2-3)
LBT	Labels (Microsoft FoxPro)
LBX	Labels (Microsoft FoxPro)
LCF	Linker control file (Norton Guides compiler)
LCH	Used in a program (unknown) that monitors a network's response time
LCK	Lockfile (Paradox)
LCL	Datafile (FTP)
LCN	Lection document (Microsoft WordPerfect for Windows)
LCS	Data History file (ACT!)
LCW	Spreadsheet (Lucid 3-D)
LD	Long distance area codes file (Telix)
LD1	Overlay file (dBase)
LDB	Lock file (Microsoft Access)
LDF	Library definition file (Geoworks Glue)
LDIF	Structured text file used for sharing information between E-Mail clients (Microsoft, Netscape and others)
LDL	Library (Corel Paradox)
LEG	Legacy document
LES	System game profiles (same as REG file) (Logitec Entertainment)
LEV	Level file (NetHack 3.x)
LEX	Dictionary file (Generic)
LFD	Data resource file (LucasArts Dark Forces)
LFP	LaserForms Plus file (Evergreen)
LFT	Loft file (3-D Studios) (DOS)
LFT	Laser printer font (ChiWriter)
LG	Logo procedure definition (LSRHS Logo)
LGC	Application log file
LGD	Application log file
LGO	Logo file (PaintBrush)
LGO	Header and footer logo (SuperFax)
LGO	Startup logo (Microsoft Windows 3.x-9.x)
LHA	Alternate file suffix for LZH
LHA	Compressed Archive (LHA/LHARC)
LHW	Compressed Amiga archive (LHWARP)
LIB	Library file (Generic)
LIF	Logical Interchange data (Hewlett-Packard)
LIF	Compressed archive (Generic)
LIM	Compressed archive (LIMIT)
LIN	Line type file (DataCad)
LIN	Interactive music sequencing data file (Electronic Arts)
LIS	Output file produced by a Structured Query Reporting (SQR) program
LIS	Listing (VAX)
LIX	Logos library system file
LJ	Text file (Hewlett-Packard LaseJet II printer)
LK	Database file (OpenSight-16 bit)
LKO	Linked object (Microsoft Outlook Express Junkmail file)
LL3	Document file (LapLink III)
LLX	Exchange agent (Laplink)
LNK	Shortcut file (Microsoft Windows 9.x)
LNK	Linker response file (RTLink)
LNK	Datafile (Revelation)
LOD	Load file (Generic)
LOG	Log file (Generic)
LOK	Compressed file (FileWrangler)
LP	A document reader used for downloading mortgage closing information (DesertDocs)
LPC	Printer driver (TEKO)
LPD	Helix Nuts and Bolts file
LPI	Information file for laser printers (common with some scanning sofware)
LRC	Video phone file (Intel)
LRF	Linker response file (Microsoft C/C++)
LRS	Language resource file (Microsoft WordPerfect for Windows)
LSF	Logos library system file
LSL	Saved library (Corel Paradox)
LSL	Script library (Lotus)
LSP	AutoLISP, CommonLISP, and other LISP language files
LSS	Spreadsheet (Legato)
LST	List file (Generic)
LST	Keyboard macro (1st Reader)
LST	Spool file (Oracle)
LTM	Form (Lotus Forms)
LU	Library unit file (ThoughtWing)
LVL	Miner Descent/D2 Level extension (Parallax Software)
LWD	Text document (LotusWorks)
LWF	Wavelet graphics file (Luratech)
LWLO	Layered Object file (Lightwave)
LWOB	Object file (Lightwave)
LWP	Wordpro 96/97 file (Lotus)
LWSC	Scene file (Lightwave)
LWZ	Linguistically enhanced sound file (Microsoft)
LYR	Layer file (DataCAD)
LZD	Difference file for binaries (Ldiff 1.20)
LZH	Compressed archive (LH ARC)
LZS	Compressed archive (LARC)
LZS	Data file (Skyroads)
LZW	Compressed Amiga archive (LHWARP)
LZX	Compressed archive (Generic)

M
M	Program file (Matlab)
M	Macro module (Brief)
M	Standard package (Mathematica)
M11	Text file (MASS11)
M1V	MPEG-related file (MIME type 'mpeg')
M3	source code file (Modula 3)
M3D	3D animation (Corel Motion)
M3U	MPEG URL (MIME audio file) (MP3 Playlist)
M4	M4 Preprocessor file (Unix)
M_U	Hard Drive Boot sector backup (MazeGold)
MA3	Macro (Harvard Graphics 3.0)
MAC	Image (MacPaint)
MAC	Macro (Generic)
MAD	Module (Microsoft Access)
MAF	Form (Microsoft Access)
MAG	A graphics format found in some Japanese files
MAG	MAG graphics format created by Woody Lynn (MPS Magro Paint System)
MAGIC	Configuration file (Magic Mail Monitor)
MAI	Mail (VAX)
MAK	Project (Visual Basic or Microsoft C++)
MAK	Makefile (Generic)
MAM	Macro (Microsoft Access)
MAN	Manual page output (Unix)
MAN	Command module (Unix)
MAP	Map file (Generic)
MAP	WAD game file (Duke Nukem 3D)
MAP	Color pallette (Generic)
MAP	Format data (Micrografx Picture Publisher)
MAP	Linker map file
MAP	Map file used for color choices (Pro/Engineer)
MAP	Map file (Atlas MapMaker)
MAP	Network map (AccView)
MAQ	Query (Microsoft Access)
MAR	Report (Microsoft Access)
MAR	Assembly program (VAX Macro)
MAR	Archive (Microstation)
	
MAS	Graphics file (Lotus Freelance Smartmaster)
MAT	Binary file (Matlab)
MAT	Table (Microsoft Access)
MAUD	Sample format (Maud)
MAX	3D scene (Kinetix 3D Studio Max)
MAX	Document (Paperport)
MAX	Layout file (OrCad)
MAX	Source code (MAX)
MAZ	Maze data file (Hover)
MAZ	A format use by Division's dVS/dVISE
MB	Memo field values for database (Paradox)
MB1	Data file (Apogee Monster Bash)
MBK	Multiple index archive (dBase IV)
MBOX	Mailbox file (Berkeley Unix)
MBX	Extension Microsoft Outlook adds to saved email, Eudora mailboxes
MCC	Calling card (Dialer10)
MCC	Configuration file (MathCad)
MCD	Document (MathCad)
MCF	Font file (MathCad)
MCF	Magic control file
MCI	Command script (Media Control Interface)
MCP	Project file (Metrowerks CodeWarrior)
MCP	Application script (Capsule)
MCP	Printer driver (MathCad)
MCR	Keyboard macro file (DataCad)
MCW	Document (Microsoft Word for Macintosh)
MCW	Text document (MacWrite II)
MD	Compressed archive (MDCD)
MDA	Add-in file (Microsoft Access)
MDA	Workgroup (Microsoft Access version 2)
MDB	Database (Microsoft Access)
MDE	MDE file (Microsoft Access)
MDL	Spreadsheet (CA-Compete!)
MDL	Music module (MOD) (Digital Trakker)
MDL	Model (3D Design Plus)
MDL	Model file (Quake)
MDL	Model file element (Rational Rose)
MDM	Modem definition (Telix)
MDN	Blank database template (Microsoft Access)
MDT	Data table (Microsoft ILink incremental linker)
MDT	Add-in file (Data) (Microsoft Access)
MDW	Workgroup (Microsoft Access)
MDX	Multiple index file (dBase IV)
MDZ	Wizard template (Microsoft Access)
ME	ASCII text document (Generic)
MEB	Macro editor bottom overflow library (Microsoft WordPerfect for Windows)
MED	Music module (MOD) (OctaMed Music Editor)
MED	Macro editor delete save file (Microsoft WordPerfect for Windows)
MEM	Macro editor macro (Microsoft WordPerfect for Windows)
MEM	Memory variable save file (Clipper)
MEM	Memory variable save file (dBase IV)
MEM	Memory variable save file (Microsoft FoxPro)
MEQ	Macro editor print queue file (Microsoft WordPerfect for Windows Library)
MER	Format for interchanging spreadsheet/database data; recognized by Filemaker, Excel, and others
MER	Macro editor resident area (Microsoft WordPerfect for Windows Library)
MES	Macro editor workspace file (Microsoft WordPerfect for Windows)
MES	Message file (Generic)
MET	Presentation Manager metafile
MET	Macro editor top overflow file (Microsoft WordPerfect for Windows Library)
MET	Document file (OmniPage Pro)
MEU	Menu group (DOS Shell)
MEX	Executable command (Matlab)
MEX	Macro editor expound file (Microsoft WordPerfect for Windows)
MF	Metafont text file
MFG	Manufacturing file (Pro/ENGINEER)
MGF	Font file (MicroGrafx)
MGF	A file in a Materials and Geometry Format
MHP	Internet mail document (Mailshift)
MHT	MHTML document (Microsoft)
MHTM	MHTML document (MIME)
MHTML	MHTML document (MIME)
MI	Data file (Cocreate ME10)
MI	Miscellaneous file (Generic)
MIC	Image Composer file (Microsoft)
MID	MIDI music
MIF	Interchange format (Adobe FramMaker)
MIFF	Machine Independent File (Generic)
MII	Datafile (MicroStat-II)
MIM	A multipart file in the Multi-Purpose Internet Mail Extensions (MIME) format; often created as the result of sending e-mail with attachments in AOL. The files in a multipart MIM file can be "opened" (unarchived and separated into individual files) using Winzip or a similar program.
MIME	See MIM.
MIX	Object file (Power C)
MIX	Picture file (Microsoft PhotoDraw 2000)
MIX	Picture file (Microsoft Picture-It!)
MIX	Package file (Command & Conquer)
MIX	Resource archive (Westwood Studios)
MJF	Audio file similar to MP3 (Mjuice) (Opens with WinAmp)
MK	Makefile (Generic)
MKE	Makefile (Microsoft Windows SDK)
MKI	Graphic Image (MagView 5.0) (Japanese)
MKS	Datafile (TACT)
ML3	Project file (Milestones 3.x)
MLB	Macro library (Symphony)
MLI	A file in 3D Studio's Material-Library format
MLID	Muliple link interface driver file (Generic)
MLM	Groupwise email file (Novell Groupwise)
MM	Text file (MultiMate Advantage II)
MMC	Catalog file (Microsoft Clip Gallery 5.x)
MMF	Mail message file (Microsoft Mail)
MME	A multipart file in the Multi-Purpose Internet Mail Extensions (MIME) format; often created as the result of sending e-mail with attachments in AOL. The files in a multipart MME file can be "opened" (unarchived and separated into individual files) using Winzip or a similar program.
MMF	Meal Master Format, a recipe catologing format
MMF	Mail file (Microsoft)
MMG	Beyond 20/20 table or aggregate data file
MML	Bulk mail file (Created by MyMailList)
MMM	Multimedia movie (Microsoft)
MMM	Multimedia movie (MacroMind Director 3.x)
MMO	Memo Writer file (RapidFile)
MMP	MindManager file (MindMapor)
MMP	Output video (Bravado)
MN2	Mission file (Descent2)
MN3	Mission file (Descent3)
MND	Menu source (AutoCAD Menu Compiler)
MND, MNI	Mandelbrot for Windows
MNG	Map (DeLorme Map'n'Go)
MNG	Multi-image Network Graphics
MNT	Menu file (Microsoft FoxPro)
MNU	Menu file (Visual dBase)
MNU	Advanced macro (HP NewWave)
MNU	Interact menu (Intertal Systems)
MNU	Menu (AutoCAD Menu Compiler)
MNU	Menu (Norton Commander)
MNX	Menu (Microsoft FoxPro)
MNX	Compiled menu (AutoCAD)
MNY	Account book (Microsoft Money)
MOB	Device definition (PEN for Windows)
MOD	FastTracker, StarTrekker, Noise Tracker (etc.) music module file
MOD	Spreadsheet (Microsoft Multiplan)
MOD	Modula-2 source code file (Clarion Modula-2)
MOD	Kernel module (Microsoft Windows 9.x)
MOD	Amiga/PC tracker module
MON	Monitor description (ReadMail)
MOV	Movie (QuickTime for Microsoft Windows)
MOV	Movie (AutoCAD/AutoFlix)
MOZ	Zipped (Compressed) mod file
MP2	MPEG Audio Layer 2
MP3	MPEG Audio Layer 3 (AC3)
MPA	MPEG-related file (MIME type 'mpeg')
MPC	Calendar file (Microsoft Project)
MPD	Database file (Microsoft Project)
MPE	MPEG animation
MPEG	MPEG animation
MPG	MPEG animation
MPM	Mathplan Macro library (Microsoft WordPerfect for Windows)
MPP	Project file (Microsoft Project)
MPP	Drawing file (CAD)
MPR	Menus (compiled) (Microsoft FoxPro)
MPT	Bitmap graphics (Multipage TIFF)
MPV	View file (Microsoft Project)
MPX	Compiled menu program (Microsoft FoxPro)
MPX	Exchange file (Microsoft Project) used for exporting data
MP2	MPEG Audio Layer 2 file (MIME video file)
MP3	MPEG Audio Layer 3 (AC3) file
MRB	Multiple resolution bitmap graphics (Microsoft C/C++)
MRI	MRI Scan
MRS	Macro resource file (Microsoft WordPerfect for Windows)
MSA	Archive (Magic Shadow)
MSC	Makefile (Microsoft C)
MSC	Common console document (Microsoft Windows 2000)
MSD	Diagnostics report file (Microsoft MSD) (Diagnostics)
MSDL	Scene Description Language (Manchester)
MSG	Mail message (Microsoft)
MSI	Installer package (Microsoft Windows)
MSN	Network document (Microsoft)
MSN	Mission File (Descent)
MSP	Paint bitmap (Microsoft)
MSP	Windows Installer patch file
MSS	Manuscript text file (Perfect Writer)
MSS	Manuscript text file (Scribble)
MSS	Manuscript text file (MINCE)
MSS	Manuscript text file (Jove)
MST	Windows Installer transform
MST	Minispecification file (Prosa)
MST	Setup script (Microsoft SDK)
MSW	Text file (Microsoft Word)
MSX	Compressed CP/M archive (MSX)
MTH	Math file (Derive)
MTM	Music module (MOD) (Multitracker)
MTW	Datafile (Minitab)
MTX	Twain device driver (32 bit)(UMax)
MU	Menu (Quattro Pro)
MUL	Online game called Ultima online
MUS	Music (Generic)
MUS	Interactive music audio data file (Electronic Arts)
MUS	Music (MusicTime)
MUS10	Audio (Mus10)
MV	Server-side script file (Miva)
MVA	Video accelerator file (Matrox)
MVB	Multimedia Viewer file (Microsoft)
MVC	Image file (Sony Digital Mavica)
MVE	Interplay video file (Descent2, Fallout2)
MVF	Stop frame file (AutoCAD-AutoFlix)
MVI	Movie command file (AutoCAD-AutoFlix)
MVW	Log file (Saber LAN)
MWF	Animation (ProMotion)
MWP	Smartmaster file (Lotus WordPro 97)
MXD	Map file (ArcInfo)
MXT	Datafile (Microsoft C)
MYP	Presentation file (Make Your Point)
 
N 
NAA	News alert advertising data (MSNBC)
NAB	News alert branding data (MSNBC)
NAC	News alert channel data (MSNBC)
NAL	News alert log file (MSNBC)
NAN	Nanoscope files (Raw Grayscale)
NAP	Metafile (NAP)
NAP	Video file (EnerGraphics)
NAS	News alert settings (MSNBC)
NB	Text file (Nota Bene)
NC	Instructions for numerical control machine (CAMS)
NCB	Developer Studio file (Microsoft)
NCC	CNC (Computer Numeric Control) file (CamView 3D)
NCD	Change directory (Norton)
NCF	Command File (Netware)
NCF	Internal clipboard (Lotus Notes)
NDB	Network database (Intellicom)
NDO	3D low-polygon modeler (Nendo)
NDX	Index file (dBase II-III-IV)
NDX	Database file (1ACT! for Microsoft Windows)
NDX	Index file (Cindex)
NEO	Raster graphics (Atari Neochrome)
NES	Emulator ROMS for game console (Nintendo)
NET	Network configuration file
NET	Netlist output file (Orcad Schematic Capture)
netCDF	Network Common Data Form
NEW	New info
NEZ	Emulator file used for game consoles (NES)
NFF	Neutral File Format
NFO	Info file database text
NFO	Infobase file (Folio)
NFT	Template file (Netobject Fusion)
NG	Online documentation database (Norton Guide)
NIL	Icon Library file (EasyIcons-compatible) (Norton)
NIST	Audio (NIST Sphere)
NLB	Data (Oracle 7)
NLM	Loadable Module (Netware)
NLS	National Language Support file used for localization (for example, by Uniscape)
NLU	E-Mail Trigger file (Norton LiveUpdate)
NLX	Form (FormWorx 3.0)
NOD	File (Netobject Fusion)
NP	Project schedule (Nokia Planner)
NP	Project schedule (Visual Planner 3.x)
NPI	Source for interpreter (dBase Application Generator)
NRF	Data file (NICOLET)
NRG	Image file (Nero)
NSF	Database (Lotus Notes)
NSO	Document file (NetObject Fusion)
NST	Music module (MOD) (Noise Tracker)
NS2	Database (Lotus Notes version 2)
NS3	Database (Lotus Notes version 3)
NS4	Database (Lotus Notes version 4)
NT	Startup files (Microsoft Windows NT)
NTF	Database template (Lotus Notes)
NTR	Executable ASCII text file
NTS	Tutorial (Norton)
NTS	Executable ASCII text file
NTX	Index file (CA-Clipper)
NUF	Message for new users (1st call) (Procomm Plus)
NWC	Song file (Noteworthy Composer)
NWS	News message (MIME RFC822) (Microsoft Outlook Express)
NXT	Sound file (NeXT)
 
O 
O	Object file (Unix)
O	Object file (Atari)
O	Object file (GCC)
OAS	Word processor document (Fujitsu OAS)(Japanese)
OAZ	Fax (NetFax Manager)
OB	Object cut/paste file (IBM LinkWay)
OBD	Binder template (Microsoft Office)
OBD	Binder (Microsoft Office)
OBJ	Object file
OBR	Object browser data file (Borland C++)
OBS	Script (ObjectScript)
OBV	Visual interface (ObjectScript)
OBZ	Binder Wizard (Microsoft Office)
OCF	Object craft file (Object Craft)
OCR	Transcribed fax-to-text file (FAXGrabber)
OCX	Object Linking and Embedding (OLE) custom control (Microsoft)
ODE	Object data embedding file (Microsoft Office)
ODL	Type library source (Visual C++)
ODS	Mailbox file (Microsoft Outlook Express)
OFD	Form definition (ObjectView)
OFF	Object File (3D Mesh)
OFN	FileNew file (Microsoft Office)
OFT	Template (Microsoft Outlook)
OKR	Feldeinteilung module file (3-D Fassade Plus)
OKT	Music module (MOD) (Oktalyzer)
OLB	Object Library (OLE) (Microsoft)
OLB	Object library (VAX)
OLD	Backup file (Generic)
OLE	OLE object
OLI	Text file (Olivetti)
OO1	Voice file (Typhoon)
OOGL	Object Oriented Graphics Library
OOM	Swap file (Shroom)
OPJ	Project file (Orcad Schematic Capture)
OPL	Organiser Programming Language source file (Psion/Symbian)
OPN	Active options (Exact)
OPO	Output executable file (OPL)
OPT	Developer Studio file (Microsoft)
OPT	Optimize support file (QEMM)
OPW	Organization chart (Org Plus for Windows)
OPX	Extension DLL (OPL)
OPX	Inactive options (Exact)
ORA	Parameter file (Oracle)
ORC	Script (Oracle 7)
ORG	Calendar file (Lotus Organizer)
OR2	Calendar file (Lotus Organizer 2)
OR3	Lotus Organizer 97 file
ORA	Configuration file (Oracle 7)
OSS	Search file (Microsoft Office)
OST	Offline file (Microsoft Exchange/Outlook)
OTL	Outline font description (Z-Soft Type Foundry)
OTL	Template file (Super NoteTab) (Fookes)
OTL	Template file (PrintMaster Gold)
OTX	Text file (Olivetti Olitext Plus)
OUT	Output file (Microsoft C)
OV	Database file (Revelation-DOS)
OV1	Overlay file 
OV2	Overlay file
OVD	Datafile (ObjectVision)
OVG	Converted graphic file (ObjectVision)
OVL	Overlay file
OVR	Overlay file
O$$	Outfile (Sprint)
 
P 
P	Source code (Pascal)
P	Application parameter file (ReaGeniX code generator)
P	Picture file (APPLAUSE)
PA1	Worktable (PageAhead)
PAB	Personal Address Book (Microsoft)
PAC	Package file (Sound Blaster Studio II)
PAC	Image (Stad)
PAD	Keypad definition (Telemate)
PAK	Compressed archive (PAK)
PAK	WAD file (Quake)
PAL	A compressed file (Generic)
PAL	Color palette (Microsoft)
PAN	Printer specific file (CorelDRAW)
PAQ	Password encrypted zip file (Hewlett-Packard)
PAR	Parts application (Digitalk PARTS)
PAR	Parameter file (Fractint)
PAR	Permanent output file (Microsoft Windows 3.x)
PAS	Source code file (Borland Pascal)
PAT	Hatch pattern file (DataCAD)
PAT	Pattern file (CorelDRAW)
PAT	Patch file (Advanced Gravis Ultrasound/Forte Technologies)
PAT	exePatch utility used for Warcraft2 (WarHack)
PB	Fax (FAXability Plus)
PB	Phone book (WinFax Pro)
PB	Setup file (PixBase)
PB1	Document (First Publisher for Windows)
PBA	Source code file (Powerbasic BASIC) (Genus)
PBD	Phone book (FaxNOW!-Faxit)
PBD	Dynamic library, an alternative to a native DLL (PowerBuilder)
PBF	Turtle Beach Pinnacle Bank File
PBI	Include file (PowerBasic) (Genus)
PBI	Profiler binary input file (Microsoft Source Profiler)
PBK	Microsoft Phonebook
PBL	Library file used in a development environment (PowerBuilder)
PBL	PowerBasic library (Genus)
PBM	Portable bitmap graphic
PBM	Planar bitmap graphic (XLib)
PBO	Profiler binary output (Microsoft Source Profiler)
PBR	Resource file (PowerBuilder)
PBT	Profiler binary table (Microsoft Source Profiler)
PC	Text file (IBM)
PC3	Custom palette (Harvard Graphics 3.0)
PC8	Ascii text IBM8 character set (NewWave Write)
PCB	Application data file (Microsoft Powerpoint)
PCB	Printed circuit layout file (Protel)
PCC	Cutout picture vector graphics (PC Paintbrush)
PCD	Image (Kodak Photo-CD)
PCD	P-Code compiled test scripts as in Microsoft Test and Microsoft Visual Test
PCE	Maps Eudora mailbox names to DOS filenames
PCF	Profiler command file (Microsoft Source Profiler)
PCH	Patch file (Generic)
PCH	Precompiled header file (Microsoft C/C++)
PCI	PCI Miniport file (Microsoft Windows System file)
PCJ	Multimedia authoring tool graphics (IBM Linkaway-Live)
PCK	Pickfile (Turbo Pascal)
PCL	Printer Control Language file (printer-ready bitmap) (Hewlett-Packard)
PCM	Audio file
PCM	PCM file (OKI MSM6376 Sythesizer Chip)
PCP	Live Update Pro file (Symantec)
PCS	Animation (PICS)
PCS	Picture storage file (Microsoft)
PCT	PICT drawing (Macintosh)
PCW	Text file (PC Write)
PCX	PC Paintbrush bitmap (ZSoft)
PDA	Bitmap graphics
PDB	Data file (TACT)
PDB	Physical model backup file (PowerDesigner)
PDB	Database file (3Com PalmPilot)
PDD	Graphic image that can be opened with Paint Shop Pro and Adobe PhotoDeluxe
PDF	Portable Document file (Adobe Acrobat) (displayable with a Web browser)
PDF	Definition File
PDF	Printer Definition File (Netware)
PDF	Graphics file (ED-SCAN 24bit)
PDL	Project description language file (Borland C/C++)
PDM	Physical model file (PowerDesigner)
PDP	Print Shop Deluxe file (Broderbund)
PDQ	Flowcharting PDQ Lite file (Patton&Patton)
PDS	Photographic image file (Print Shop Deluxe)
PDS	Hardware assembly source code file (Pldasm)
PDT	Database file (ProCite)
PDV	Printer driver (Paintbrush)
PDW	Document (Professional Draw)
PDX	Database index file (ProCite)
PE3	Image archive file (Ulead PhotoImpact)
PE3	Image archive file (QuickViewer)
PE4	Image archive file (Ulead PhotoImpact v.4.0)
PEB	Program Editor bottom overflow file (Microsoft WordPerfect for Windows Library)
PED	Program Editor delete save file (Microsoft WordPerfect for Windows)
PEM	Program Editor macro (Microsoft WordPerfect for Windows library)
PEQ	Program Editor print queue file (Microsoft WordPerfect for Windows)
PER	Program Editor resident area file (Microsoft WordPerfect for Windows Library)
PES	Program Editor work space file (Microsoft WordPerfect for Windows Library)
PET	Program Editor top overflow file (Microsoft WordPerfect for Windows Library)
PF	Encrypted file (Alladin Systems)
PFA	Type 3 font (ASCII)
PFB	Type 1 font (binary)
PFC	PF Component file
PFC	Text file (First Choice)
PFC	Personal filing cabinet file (AOL)
PFF	Paraform file for 3D modeling (Scandata)
PFK	Programmable function keys (XTreePro)
PFM	Printer Font Metrics (Microsoft)
PFS	Database text file (PFS:Write)
PFT	Printer font (ChiWriter)
PG	Page cut/paste file (IBM LinkWay)
PGI	Printer graphics file device driver (PGRAPH Library)
PGL	Plotter drawing (Hewlett-Packard)
PGM	Portable Graymap (bitmap)
PGM	Program file (Signature)
PGN	Portable game notation file (ChessMaster and others)
PGP	PGP encrypted file
PGS	Manual page (man4dos)
PH	Temporary file generated by Microsoft Help Compiler
PH	Optimized .goh file (Geoworks)
PH	Perl header file
PH	Phrase-table (Microsoft C/C++)
PHN	Phone list (UltraFax)
PHN	Phone list (QmodemPro)
PHO	Phone database (Metz Phone for Windows)
PHP	HTML page that includes a PHP script
PHP3	HTML page that includes a PHP script
PHR	Phrases (LocoScript)
PHTML	HTML page that includes a PHP script
PHTML	Perl-parsed HTML
PI1	Low resolution picture file (Dages Elite)
PI2	Medium resolution picture file (Dages Elite)
PI3	High resolution picture file (Dages Elite)
PIC	Bitmap (PC Paint)
PIC	Pixar picture file (SDSC Image Tool)
PIC	Picture file (Lotus)
PIC	PICT drawing (Macintosh)
PIC	3D Image file (SoftImage)
PICT	PICT image file (Macintosh)
PIF	Program Information File
PIF	PIF drawing (IBM)
PIF	Vector graphics GDF file (IBM Mainframe)
PIF	Compressed archive (Macintosh)
PIG	WAD file (Lucas Arts Dark Forces)
PIN	Data file (Epic Pinball)
PIN	Data file (Epic Pinball)
PIX	Bitmap (Inset Systems)
PIX	Alias image file (SDSC Image Tool)
PJ	Project file (CA-SuperProject)
PJ	Source Integrity file (MKS)
PJT	Visual FoxPro memo file (Microsoft)
PJT	Visual Foxpro Project (Microsoft)
PJX	Visual FoxPro project file (Microsoft)
PK	Packed bitmap font file (TeX DVI)
PKA	Compressed file archive (PKARC)
PKG	Developer Studio application extension (similar to a DLL file) (Microsoft)
PKG	Installer script (NEXT)
PKR	Public Keyring (PGP)
PKT	Packet file (Fidonet)
PL	Interleaf printerleaf (or WorldView) format
PL	Source code file (Perl)
PL	Source code file (Prolog)
PL	Property list font metric file (TeX)
PL	Palette (Harvard Graphics)
PL1	Room plan (3D Home Architect)
PL3	Chart palette (Harvard Graphics 3.0)
PLB	Library file (Microsoft FoxPro)
PLC	Add-in file (Lotus 1-2-3)
PLG	A format use by REND386/AVRIL
PLI	Data description file (Oracle 7)
PLL	Pre-linked library file (Clipper 5)
PLM	Module (DisorderTracker2)
PLN	Spreadsheet (Microsoft WordPerfect for Windows)
PLR	Pilot file (Descent 1-3)
PLS	Sample file (DisorderTracker2)
PLS	MPEG PLayList file (used by WinAmp)
PLT	Drawing (HPGL Plotter)
PLT	Plot drawing (AutoCAD)
PLT	Palette (Generic)
PLT	Pre-linked transfer file (Clipper 5)
PLT	Sign-making software (Gerber Optical)
PLY	Data file (PopMail)
PLY	Presentation screen (Harvard Spotlight)
PM	Bitmap graphics (Presentation Manager)
PM	Module (Perl)
PM3	Document (PageMaker 3.0)
PM4	Document (PageMaker 4.0)
PM5	Document (PageMaker 5.0)
PM6	Document (PageMaker 6.0)
PMA	Data file (Performance Monitor)
PMC	Graphics (A4TECH Scanner)
PMM	Program file (Amaris BTX/2)
PMR	Data file (Performance Monitor)
PMW	Data file (Performance Monitor)
PN3	Printer device driver (Harvard Graphics 3.0)
PNG	Bitmap (Portable Network Graphics)
PNG	Browser catalogue (Paint Shop Pro)
PNG	Bitmap file (MacroMedia FireWorks)
PNM	Portable aNY Map graphics (PBM)
PNT	Graphic file (MacPaint)
PNT	QWK reader pointer file (MarkMail 2.x)
PNT	Pen Table plotting file (Pro/Engineer)
PNTG	Same as PNT file
POG	PIG file extension (Descent2)
POH	Optimized .goh file (Geoworks)
POL	Windows NT Policy file
POL	3D polygonal modeling file (Innovmetric)
POP	Popup file (Visual dBase)
POP	Message index (PopMail)
POT	PowerPoint template (Microsoft)
POV	Persistence of Vision file (Ray-Tracer)
POW	Chord chart (PowerChords)
PP	Compressed Amiga archive (POWERPACKER)
PP4	Bitmap (Picture Publisher 4)
PPA	PowerPoint Add-in (Microsoft)
PPB	Button bar for print preview (Microsoft WordPerfect for Windows)
PPD	PostScript Printer definition file specification (Adobe Acrobat v.4.0)
PPF	Pinnacle Program File (Turtle Beach)
PPI	Graphics file (Microsoft PowerPoint)
PPL	PolaroidPalettePlus ColorKey device driver (Harvard Graphics 3.0)
PPM	Portable Pixelmap bitmap
PPO	Pre-processed output file (Clipper 5)
PPP	Document or finished project (Parson Power Publisher)
PPP	Desktop publishing default output file (Serif PagePlus)
PPS	PowerPoint slide show (Microsoft)
PPS	Storyboard (Personal Producer)
PPT	PowerPoint presentation (Microsoft)
PPZ	PowerPoint "pack and go" presentation (Microsoft)
PQB	Master boot backup file (PowerQuest BootMagic)
PQI	Drive image file (PowerQuest)
PR2	Presentation (Aldus Persuasion 2.x)
PR2	Printer driver (dBase IV)
PR3	Postscript printer driver (dBase IV)
PR3	Presentation (Aldus Persuasion 3.x)
PRC	Resource (text or program) file (3com PalmPilot)
PRD	Printer driver (Generic)
PRE	Presentation (Lotus Freelance)
PRE	Settings (Programmer's WorkBench)
PRE	Settings (Microsoft C/C++)
PRF	System file (Microsoft Windows)
PRF	Settings file (Macromedia Director)
PRF	Pixel Run Format graphics (Improces-Fastgraph)
PRF	Printer driver (dBase IV)
PRF	Output file (Profiler)
PRG	Program source files (dBase IV, Clipper 5, and Microsoft FoxPro)
PRG	Program source files (Atari)
PRG	Program file (WAVmaker)
PRI	Printer definitions (LocoScript)
PRJ	Project file (3D Studio) (DOS)
PRM	Parameter file (Generic)
PRN	Print Table (space delimited text)
PRN	Windows Printer file (DataCAD)
PRN	Printer driver (Signature)
PRN	Text file (Lotus 1-2-3-Symphony)
PRO	Source code file (Prolog)
PRO	Configuration file (Pro/Engineer)
PRO	Graphics profile file (DOS)
PRO	Graphics file (Pagis Pro 3.0)
PRO	Project file (Terramodel)
PRP	Data conversion saved project file (Oberon Prospero)
PRS	Presentation file (Harvard Graphics for Windows)
PRS	Printer resource font file (Microsoft WordPerfect for Windows)
PRS	Procedure file (dBase IV)
PRT	A print-formatted file
PRT	Printer driver (Dr. Halo)
PRT	Part file (SolidWorks)
PRT	Part file (Pro/Engineer)
PRT	Part file (CADkey)
PRV	Internet provider template file (psiMail)
PRX	Compiled program (Microsoft FoxPro)
PRZ	Graphics file (Lotus Freelance 97)
PS	Postscript-formatted file (a Postscript printer-ready file)
PSB	Sound Bank file (Pinnacle)
PSD	Bitmap (Adobe Photoshop)
PSE	Bitmap graphics (IBM printer Page SEgment)
PSF	Outline PostScript printer font (ChiWriter)
PSI	A-law audio file (psion)
PSM	Studio module (ProTracker) 
PSM	Sound data file (Epic Pinball)
PSM	Symbol table of IDE (Turbo Pascal)
PSP	Image file (PaintShop Pro)
PSP	Procedure (Prodea Synergy)
PSP	Psotscript prepped imposed print file (Scenicsoft Preps)
PSR	Report file (PowerSoft)
PST	Personal Folder File (Microsoft Outlook)
PT3	Device driver (Harvard Graphics 3.0)
PT3	Template (PageMaker 3.0)
PT4	Template (PageMaker 4.0)
PTB	Script file (PubTech BatchWorks)
PTB	Table file (Pro/Engineer)
PTD	Table file (Pro/ENGINEER)
PTL	Petal file (ASCII version of Microsoft Visual Modeler)
PTM	Macro (PubTech BatchWorks)
PTM	Music module (MOD) (Polytracker)
PTR	QWK reader pointer file (QMail)
PUB	Publication (Ventura Publisher)
PUB	Document (Microsoft Publisher)
PUB	Public key ring file (PGP)
PUD	Map file (WarCraftII)
PUT	Compressed archive (PUT)
PVD	Script file (Instalit)
PVL	Library file (Instalit)
PVT	Local pointlist (Fidonet)
PW	Text file (Professional Write)
PWD	Word document (Microsoft Pocket)
PWL	Password list file (Microsoft Windows 9.x)
PWP	Image file (a roll of film viewed using Photoworks)
PWP	Text document (Professional WritePlus)
PWZ	PowerPoint wizard (Microsoft)
PX	Primary database index (Paradox)
PXL	Pocket Excel spreadsheet (Microsoft)
PY	Saved emessages (YAHOO)
PY	Python Script file
PYC	Python Compiled script file
PZD	Default settings (Pizazz Plus)
PZO	Overlay file (Pizazz Plus)
PZP	Palette (Pizazz Plus)
PZS	Settings (Pizazz Plus)
PZT	Transfer file (Pizazz Plus)
PZX	Swap file (Pizazz Plus)
P3	Project Planner file (Primavera)
P7S	Digital ID file (S/MIME), used in digitally signed internet mail
P10	Plot 10 drawing (Tektronics)
P10	Digital ID file (S/MIME), Used in digitally signed internet mail
P12	Digital ID file (S/MIME), (used to store dititally encrypted, or signed internet mail files)
P16	16 Channel Music file (ProTracker 16)
P22	Patch file (Patch 22)
P65	Document file (PageMaker 6.0)
P7C	Digital ID file (S/MIME), Used in digitally signed internet mail
P7M	Digital ID file (S/MIME), used in digitally signed internet mail
 
Q 
QAD	Document (PF QuickArt)
QAG	Quick Access Group data file (Norton Desktop)
QAP	Application file (Omnis Quartz)
QBE	Saved query (dBase IV)
QBE	Saved Query (Quattro Pro)
QBO	Compiled query (dBase IV)
QBS	Program file (Microsoft QuickBasic)
QBW	Spreadsheet data (QuickBooks for Windows)
QCP	Voice file (Qualcomm Pure Voice)
QD0	Data file-segment 10 (Omnis Quartz)
QD1	Data file segment 1 (Omnis Quartz)
QD2	Data file segment 2 (Omnis Quartz)
QD3	Data file segment 3 (Omnis Quartz)
QD3D	QuickDraw 3D Metafile (Apple)
QD4	Data file segment 4 (Omnis Quartz)
QD5	Data file segment 5 (Omnis Quartz)
QD6	Data file segment 6 (Omnis Quartz)
QD7	Data file segmnet 7 (Omnis Quartz)
QD8	Data file segment 8 (Omnis Quartz)
QD9	Data file segment 9 (Omnis Quartz)
QDF	Data file (Quicken)
QDK	Backup of startup files (QEMM)
QDT	Data file from the Quicken UK Accountancy/Tax/Invoice program (QuickBooks)
QDV	Graphics file (Steve Blackstock Giffer)
QEF	Query file (Microsoft Excel)
QEL	Electronic library file (Quicken)
QFL	Document (FAMILY LAWYER)
QFX	Fax (QuickLink)
QIC	Backup file (Microsoft)
QIF	Image (MIME)(QuickTime)
QIF	Import file (Quicken)
QLB	Library file (Quick)
QLB	Library file (Microsoft C/C++)
QLC	Data (PostScript help file)
QLP	Printer driver (QuickLink)
QM	Motion file (Quality)
QM4	Option or services file (QMail 4.x Mail Door)
QPR	Generated query program (Microsoft FoxPro)
QPR	Print queue device driver (OS/2)
QPW	Project file (Quattro Pro)
QPX	Compiled query program (Microsoft FoxPro)
QQT	Qardware definition file (Quick Qard Technology)
QRP	Report builder file (Centura)
QRP	Report file (Liberty for Windows 2.0)
QRS	Equation Editor support file (Microsoft WordPerfect for Windows)
QRT	QRT graphics file (Ray Tracer)
QRY	Query (Microsoft)
QRY	Query (dBase IV)
QSD	Datafile (Quicken)
QST	Tab file (Quake Spy)
QT	Movie file (QuickTime)
QTI	Image file (QuickTime)
QTIF	Image file (QuickTime)
QTM	Movie file (QuickTime)
QTP	Preferences file (QuickTime)
QTS	PICT image file (Macintosh)
QTS	Image file (QuickTime)
QTX	Image file (QuickTime)
QW	Write program file (Symantec Q&A)
QWK	Message file (QWK Reader)
QXD	Data file (Quark Xpress)
QXL	Element library (Quark Xpress)
QXT	Template file (Quark Xpress)
 
R 
R	Ratfor file (FORTRAN Preprocessor)
R	Resource file (Pegasus Mail)
RA	Sound file (RealAudio)
RAD	Radar data file (Radar ViewPoint)
RAM	Metafile (RealAudio)
RAO	ReadAllOver (YOUniverse)
RAR	RAR compressed archive (Eugene Roshall's format)
RAS	Bitmap (Sun Raster Images)
RAT	Datafile (RATS)
RAW	Raw File Format (bitmap)
RAW	Raw signed PCM data
RAW	Raw signed PCM data
RBF	Datafile (Rbase)
RBH	Maintained by RoboHELP, the RBH file adds to the information contained in the Help project file
RC	Resource script (Micosoft C/C++)
RC	Resource script (Borland C++)
RC	Configuration file (emacs)
RCG	Newsgroup file (Netscape)
RD1	Registered level file (Descent1)
RDF	Resource Description Framework file (related to XML and metadata)
RDF	Compiled UIC source code (Geoworks UI Compiler)
RDF	Research document information format
RDI	Device-independent bitmap file
RDL	Registered Level file (Descent)
RDX	Datafile (Reflex)
REC	Datafile (EpiInfo)
REC	Recorded macro (Microsoft Windows 3.x)
REC	Voice file (RapidComm)
REC	Record file (Sprint)
RED	Path information file (Clarion Modula-2)
REF	Reference file (Generic)
REG	Registration file
REG	Registration file (Corel)
REG	OLE registration file (Microsoft Windows 3.x)
REM	Remarks file (Generic)
REP	Reply file (QWK Reader)
REP	Report file (Visual dBase)
REP	Report file (Report Designer)
REP	Report file (DataBoss)
REP	Report file (CodeReporter)
REQ	Request file (Generic)
RES	Resource file (Microsoft Visual C++)
RES	Compiled resource file (Borland C++)
RES	Resource file (dBase IV)
REV	Revision file (GeoWorks)
REX	Source code file (REXX)
REX	Report definition (Oracle)
REZ	Resource file (Generic)
RF	Raster graphics file (Sun)
RFT	Revisable Form Text (part of IBM's DCA or Document Content Architecture)
RGB, SGI	RGB files (Silicon Graphics)
RGX	Symbol tables (ReaGeniX code generator)
RH	Resource header file (Borland C++ 4.5)
RI	Data file (Lotus 1-2-3)
RIB	Graphics in Renderman format (3DReality)
RIC	Fax document (Ricoh)
RIF	RIFF bitmap graphics (Fractal Design Painter)
RIF	Image file (Metacreations Painter 5)
RIP	Graphics (remote access)
RIX	Bitmap graphics (ColorRIX VGA Paint)
RL1	Regestered level file (Descent1)
RL2	Registered level file (Descent2)
RL4	Bitmap graphics file
RL8	Bitmap graphics file
RLA	Wavefront raster image (SDSC Image Tool)
RLB	Data file (Harvard Graphics Win 9.x)
RLC	Graphics file (1 bit per pixel scanner output file)
RLE	Run-Length Encoded bitmap (SDSC Image Tool)
RLZ	Realizer source code file (CA-Realizer)
RM	Video file (RealAudio)
RMD	Document (Microsoft RegMaid)
RMF	Rich Map Format (used by 3-D game editors to store a map)
RMF	Rich music format (Beatnik)
RMI	MIDI music
RMK	Makefile (Clipper RMake)
RN	Xpl Program file (Nota Bene)
RND	Rendering slide (AutoCAD-AutoShade)
RNO	Runoff file (VAX)
ROL	FM music Adlib Music file (Roland)
ROM	Cartridge-based home video game emulator file (exact copy of ROM contents in cartridges from Atari 2600, Colecovision, Sega, Nintendo, etc.; not interchangeable between emulators)
ROV	Data file (Rescue Rover)
RPD	Database (RapidFire)
RPL	Text document (Replica)
RPL	Video file (Tomb Raider)
RPM	Package Manager (RedHat Linux)
RPT	Crystal Reports file ( and a sub-set of Microsoft Visual Basic)
RRS	Saved game file (Ace Road Rash)
RS	Datafile (Amiga Resource Reassembler)
RSB	Red Storm bitmap (Rainbow 6 (Game) and several image editing programs)
RSC	Resource file (Generic)
RSL	Paradox 7 reports (Broderland)
RSM	Resume file (WinWay Resume Writer)
RSP	Response file (Generic)
RS_	Resourse fork file (Macintosh Mac-ette)
RTF	Rich Text Format document
RTF	Help file script (Microsoft Windows 9.x)
RTL	Run Time library (NU 7.0)
RTM	Music module (MOD) (Real Tracker)
RTK	Used by RoboHELP to simulate the search feature of Windows help
RTL	Text file (Generic)
RTP	Software update package data file (RTpatch)
RTS	RTSL document (RealAudio)
RTS	Runtime library file (CA-Realizer)
RTS	RoboHELP to speed complex operations
RUL	Extension used in InstallShield
RUN	Compiled output p-code file (Softworks basic compiler) (SoftworksLtd)
RVP	Scan Configuration file (MIME) (Microsoft)
RVW	Review file (Generic)
RWS	Resource Workshop data file (Borland C++)
RWX	Script file (RenderWare)
RXX	RAR compressed files from a multi-volume archive (xx = a number from 01 to 99)
R8	Raw graphics (One byte per pixel) plane one (PicLab)
R8P	Pcl 4 bitmap font (Intellifont)
 
S 
S	Assembler source code (Unix)
S	Source code file (Scheme)
SAI	Encrypted video file (Integrated Sensors)
SAL	Datafile (SORITEC)
SAM	Document (AMI Professional)
SAM	Signed 8bit sample data file
SAR	Compressed archive (SAR)
SAR	Shell archive file
SAV	Saved game file (Generic)
SAV	Backup file (Generic)
SAV	Configuration file (Generic)
SB	Raw Signed Byte (8bit) audio data
SBD	Storyboard data file (Storyboard Editor)
SBD	Data definition file (Superbase)
SBF	File data (Superbase)
SBI	Instrument file (Creative Labs SoundBlaster)
SBK	Bank file (Soundblaster)/EMU SoundFont v1.x (Creative Labs Soundfont 1.0)
SBL	Flash object (ShockWave)
SBP	Dml program file (Superbase 4)
SBP	Program file (Superbase)
SBQ	Query definition file (Superbase)
SBR	Support file (Source Browser)
SBT	Notes related to record data (Superbase 4 for Windows)
SBV	Form definition file (Superbase)
SB!	Locking file (Superbase)
SC	Pal script (Paradox)
SC	Display driver (Framework II)
SC2	Schedule+ 7.0 file (Microsoft)
SC2	SAS catalog (Windows 95/NT, OS/2, Mac)
SC3	Saved game file (SIMM City 3000)
SC3	Renamed dBase III screen mask file (dBase IV)
SC3	Screen device driver (Harvard Graphics 3.0)
SC4	Level file (Roller Coaster Tycoon)
SCA	Datafile (SCA)
SCC	Source Safe file (Microsoft)
SCC	Text file (Generic)
SCD	Slide image (Matrix/Imapro SCODL)
SCD	Object description language graphics (Scodl Scan Conversion)
SCD	Datafile (Microsoft Schedule+ 7.0)
SCF	Command file (Microsoft Windows Explorer)
SCF	Multimedia show (ScoreMaker)
SCF	Spell checker configuration file (Symphony)
SCH	Datafile (Microsoft Schedule+ 7.0)
SCH	Schematics file (ORCAD)
SCI	Inspire native format (ScanVec)
SCI	System configuration information file (Generic)
SCI	Fax document (SciFAX)
SCM	Scheme source code file (Generic)
SCM	Video game console ROM emulater file
SCN	Scene data file (TrueSpace2)
SCN	Screen file (Kermit)
SCO	High score file (Generic game file)
SCP	Dial-Up Networking Script
SCP	Script file (BITCOM)
SCR	Screensaver file (Microsoft Windows 9.x)
SCR	Fax image (Generic)
SCR	Debug source code (DOS Debug)
SCR	Screen snapshot file (dBase IV)
SCR	Screen snapshot file (Procomm Plus)
SCR	Screen font file (LocoScript)
SCT	SAS catalog (Dos)
SCT	CT bitmap (Scitex)
SCT	FoxPro forms (Microsoft)
SCT01	SAS catalog (Unix)
SCV	CASmate Native format (ScanVec)
SCX	FoxPro forms (Microsoft)
SCX	Bitmap graphics (ColorRIX)
SCX	Chart (Stanford Chart)
SCX	Screen file (Microsoft FoxPro)
SCY	Security file (ReaGeniX)
SD	Audio (Sound Designer I)
SD2	Flattened file/data fork (Sound Designer II)
SD2	SAS database (Windows 95/NT OS/2, Mac)
SDA	File archive description (Fidonet Software Distribution Network)
SDC	Spreadsheet (Staroffice)(StarCalc)
SDD	Presentation file (Staroffice)(Starimpress)
SDF	System Data File Format - legacy Unisys (Sperry) format
SDI	Software distribution network information file
SDK	Floppy disk image (Roland)
SDL	Library file (SmartDraw)
SDN	Software distribution network compressed archive
SDP	Datafile (Cocreate SolidDesigner)
SDPC	Datafile (Cocreate SolidDesigner)
SDR	Drawing (SmartDraw)
SDS	Raw Midi Sample Dump Standard file
SDT	Template (SmartDraw)
SDV	Semicolon Divided Values file
SDW	Graphic file (Lotus WordPro)
SDW	Raw Signed DWord (32bit) data
SDW	Datafile (Scenery data for Windows)
SDX	Midi Sample Dump Standard files compacted by SDX
SEA	Self-expanding archive (used by Stuffit for Mac files and possibly by others)
SEC	Secret key ring file (PGP)
SEC	Secured animation file (Disney Animation Studio)
SED	Screen editor script files (SED)
SEL	Data file (Copy Books)
SEP	Tagged Image File Format (TIFF) bitmap
SEP	Printer seperator page (Generic)
SEQ	Animation file (Atari)
SEQ	Sequential instruction file (Bubble Chamber)
SES	Session file (Cool Edit) (common digital audio editor file )
SES	Session information file (Clarion Modula-2)
SESSION	Internet Security Scanner file (ISS)
SET	Configuration file (1st Reader)
SET	Install driver sets (Symphony)
SET	Setup option file (Generic)
SET	Voice set files (Quartet)
SEW	Sewing program file (Generic)
SF	SoundFile format (IrCam)
SF	Wps attribute storage file (OS/2 WorkPlace Shell)
SF2	SoundFont file (EMU version 2.0)
SF2	Bank file (Creative Labs Soundfont 2.0)(Soundblaster)
SFD	Sound File Data (SoundStage)
SFI	Sound File Info (SoundStage)
SFI	Graphics file (SIS Framegrabber)
SFI	Printer font file (Hewlett-Packard Laser Jet Landscape)
SFI	Printer font file (Ventura Publisher)
SFK	Sound file (Sonic Foundry)
SFL	Pcl 4 bitmap font (LandScape)
SFL	Pcl 4 bitmap font (Ventura Publisher)
SFL	Pcl 4 bitmap font (Intellifont)
SFN	Font file (SPX)
SFP	Pcl bitmap font (Portrait)
SFP	Pcl bitmap font (Intellifont)
SFP	Pcl bitmap font (Ventura Publisher)
SFR	Sample Resource (Sonic Foundry)
SFS	Pcl 5 scalable font file (Intellifont)
SFT	Screen font (ChiWriter)
SFW	Mangled JPEG (Seattle Filmworks)
SFX	Self-extracting archive (RAR)
SG	Image file (SnapGraphix)
SG1	Graphics file (Stanford Graphics)
SGF	Document w/graphics (StarWriter)
SGF	Graphics file (Sonique)
SGI	Graphics file (IRIS)
SGI	Graphics file (Silicon Graphics)
SGML	Standard Generalized Markup Language
SGP	Statistics file (STATGRAPHICS Plus)
SGT	Save/Get keyboard macro (Signature)
SH	Shell script (Unix)
SH	ASCii archive (Unix/SHAR)
SH3	Presentaion file (Harvard Graphics)
SHB	Presentation (Corel Show)
SHB	Document shortcut file
SHG	Bitmap (HotSpot)
SHK	Compressed Apple archive (SHRINKIT)
SHK	Compressed archive (Arthurian Shrink Archiver)
SHM	Shell macro (Microsoft WordPerfect for Windows Library)
SHN	Audio compression file (Shorten)
SHP	DOS shapes file (3D Studios)
SHP	File format used by some programs for 3D modeling of multipart interactive triangle models
SHP	Shapefile spatial data format (used by many GIS programs)
SHP	Source code and shape file for text fonts (AutoCAD)
SHR	File archive (Unix ASCii) (SHAR)
SHS	Shell scrap file; reportedly used to send "password stealers"
SHT	Proprietary html format for Netscape, (Now AOL)
SHTML	HTML file containing Server Side Includes (SSI)
SHW	Presentation (Corel Show)
SHW	Presentation (Harvard Graphics 2.0)
SHW	Slide Show (Microsoft WordPerfect for Windows)
SHX	Shape entities (AutoCAD)
SHX	Shapefile spatial index file (ArcView)
SID	Audio music (SidPlay)
SID	Image file (MrSID)(LizardTech)
SIF	Setup installation files (Microsoft Windows NT)
SIG	Signature file (PopMail)
SIG	Current program settings (Signature)
SIK	Backup files (Microsoft Word for Windows)
SIK	Backup files (Sicherungskopie)
SIT	Compressed archive of Mac files (Stuffit)
SIZ	Configuration file (Oracle 7)
SKA	Secret Keyring file (PGP)
SKF	Drawing file (AutoSketch)
SKL	Resource file (Macromedia Director)
SL	Save Layout extension (PACT)
SL	Source code file (S-Lang)
SLB	Slide Library File (AutoCAD)
SLC	Compiled SALT script (Telix)
SLD	Slide File (AutoCAD)
SLI	Slide file (MAGICorp Slide Service)
SLK	Symbolic link spreadsheet (SLYK)
SLL	Sound data file (Generic)
SLT	Script application language (SALT) (Telix script source)
SM	Source code file (Smalltalk)
SM	Maillist (SoftSpoken Mailer)
SM	Script file (ScriptMaker)
SM	Text file (Samna Word)
SM3	Symbol file (DataCAD)
SMD	Video game console ROM emulator file
SMF	Fax document (SMARTFAX)
SMK	Image file (Deer's Revenge)
SMK	Image file (Smack Player)
SMK	Image file (Nascar Racing '99)
SMM	Macro (AMI Pro)
SMP	Samplevision format
SMP	Sample file (AdLib Gold)
SMS	Emulator ROM image file (8-bit Sega Master System)
SMT	Text file (Smart Ware II)
SMT	SmartObject file (IconAuthor)
SND	Sound file (NeXt)
SND	Sound resource (Macintosh)
SND	Raw unsigned PCM data
SND	Sample (AKAI MPC)
SNDR	Sound file (Sounder)
SNDT	Sound file (SndTool)
SNG	Midi song file (Midisoft Studio)
SNG	Midi song file (Prism)
SNM	Mailbox (mail folder) index (Netscape)
SNO	Source code file (Snobol4)
SNP	Output video file (Computer Eyes)
SNP	Database file (Microsoft Access) opens with "Snap Viewer, from Microsoft")
SO	Shared library file (Unix)(equivalent to a Windows DLL)
SOL	Solution file (Common used with game examples,tutorials)
SOM	Network serial numbers (Quattro Pro)
SOM	Sort information files (Paradox)
SON	Song file (Creative Labs SoundBlaster Studio II)
SOU	Sound file (Creative Labs SoundBlaster Studio)
SOX	Schema for object oriented XML
SP	Compressed archive for Unix (Sprint)
SP4	Saved game (Roller Coaster Tycoon)
SPC	Program file (Microsoft MultiPlan)
SPC	Temporary file (Microsoft WordPerfect for Windows)
SPD	Data file (Speech)
SPD	Scalable font (Speedo)
SPD	Scalable font (Harvard Graphics 3.0)
SPF	Slide presentation file (EnerGraphics)
SPG	Glossary file (Sprint)
SPI	Graphics file (Siemens Scanner)
SPI	Graphics file (Phillips Scanner)
SPL	Object file (ShockWave Flash)
SPL	Sample file (DigiTracker)
SPL	Compressed archive (SPLINT)
SPL	Customized printer driver (Sprint)
SPL	Personal spell dictionary (Signature)
SPL	Printer spool file (Microsoft Windows 3.x)
SPL	Sample file (Generic)
SPM	Data file (Microsoft WordPerfect for Windows)
SPP	Printer file (Sprint)
SPPACK	Sound sample (SP Pack)
SPR	Document letter (Sprint)
SPR	Generated screen program (Microsoft FoxPro)
SPR	Sprite (Image layering and resizing)
SPRITE	Bitmap file (Acorn)
SPS	Spssx source code file (VAX/VMS)
SPS	Screen driver (Sprint)
SPT	Source code file (Spitbol)
SPT	Support file (MITAC disk/system management utility package)
SPU	Picture file (Spectrum 512)
SPW	Worksheet (SigmaPlot)
SPX	Compiled screen program (Microsoft FoxPro)
SQC	Structured Query Language (SQL) common code file
SQL	SQL queries (Informix)
SQL	Generally used by database products as an extension for SQL queries (scripts, text, or binary)
SQP	Query result of audio search (Sonique)
SQR	Structured Query Language (SQL) program file
SQZ	Compressed archive (SQUEEZE)
SRE	Undefined file (Motorola)
SRF	Raster graphics file (Sun)
SRM	Video game console ROM emulator file
SRP	SCript file (QuickLink)
SRZ	Source file (DataFlex)
SS	Bitmap graphics (Splash)
SSA	Video file (Sub Station Alpha)
SSD	Datafile (SAS/PC)
SSD01	SAS data sets (Unix)
SSD	SAS database (Dos)
SSF	Spreadsheet file (Enable)
SSP	Datafile (SAS Transport)
ST	Source code file (Little SmallTalk)
ST	Instrument library (Scream Tracker)
ST	Disk Image file (Atari)
ST	Stamp file (NeoPaint)
STA	Saved state (Reflection 4.0)
STA	Stack file (SpinMaker Plus)
STB	Stub library (Genus GX Kernel)
STD	State transition diagram graphic file (Prosa)
STD	Standard script file (LocoScript)
STF	Compressed archive (SHRINKTOFIT)
STL	Stereolithography file
STM	Shorter suffix for .shtml, an HTML file containing a server side include (SSI)
STM	Music module (MOD) (Scream Tracker 2)
STM	State transition diagram model file (Prosa)
STM	Music file (Scream Tracker)
STO	Pascal stub OBJ file (Genus GX Kernel)
STQ	Text file (Statistica) (StatSoft Software)
STR	Screensaver file
STR	Structure list OBJ file (dBase IV Application Generator)
STS	Project status information file (Microsoft C/C++)
STS	Song file (Music) (Scream Tracker)
STY	Style sheet (Ventura Publisher)
STW	Data file (SmartTerm for Windows)
STX	Electronic book file (SmarText)
STX	Tax form (CA-Simply Tax)
STY	Style sheet (Generic text and graphics programs0
SUI	Suit library (Simple User Interface Toolkit)
SUM	Summary file (Generic)
SUN	Rasterfile graphics (Sun)
SUP	Supplementary dictionary files (Microsoft WordPerfect for Windows)
SVD	Autosave file for document (Microsoft WordPerfect for Windows)
SVF	Simple Vector Format 2D image (Microstation)
SVG	Autosave file for glossary (Microsoft WordPerfect for Windows)
SVG	Scalable vector graphics file (Adobe)
SVP	Graphics file (Sonique)
SVS	Autosave file for style sheet (Microsoft WordPerfect for Windows)
SVX	Sound file (Amiga 8SVX)
SVX	Interchange file format, 8SVX/16SV
SVY	Database file (SAVVY/PC)
SW	Raw signed Word (16bit) data
SWA	Shockwave audio file in Macromedia Director (an MP3 file)
SWF	Object (ShockWave Flash)
SWG	Swag Packet file (SWAG Reader)
SWP	Swap file (DataCAD)
SWP	Document backup file (Sprint)
SWP	Swap file (DOS)
SY1	Smartpix symbol library (Ami Pro)
SY3	Symbol file (Harvard Graphics 2.0)
SYD	Backup of startup files (QEMM)
SYM	Precompiled header file (Borland C++)
SYM	Program symbol table (Generic to compilers)
SYM	Symbol file (Harvard Graphics 2.0)
SYN	SDSC Synu image file (SDSC Image Tool)
SYN	Synonym file (Microsoft Word 5.0)
SYS	System file (Generic)
SYS	Datafile (SYGRAPH)
SYS	Datafile (SYSTAT)
SYS	Datafile (SPSS/PC)
SYS	System file Device driver or hardware configuration file
SYW	Wave file (Yamaha SV-series)
SYW	Graphics symbols (Harvard Graphics)
S3I	Instrument file (Scream Tracker v 3.0)
S3M	16 channel music file (Scream Tracker v 3.0)
S$$	Temporary sort file (Sprint)
 
T 
T	Source file (TADS)
T	Tape archive (TAR) (Without compression)
T	Tester symbol file (ReaGeniX code generator)
TAB	Table file (MapInfo GIS)
TAB	Guitar Tablature file
TAG	Query tag name file (DataFlex)
TAH	Turbo assembler help file (Borland C++)
TAL	Text illustration file (TypeAlign)
TAR	Tape Archive
TAR	Compressed archive (TAR)
TAX	Data file (Turbo Tax)
TAZ	Gzip/Tape archive (Unix)
TAZ	Compressed ASCII archive (TAR)
TAZ	Compressed ASCII archive (COMPRESS)
TB1	Font file (Borland Turbo C)
TB2	Font file (Borland Turbo C)
TBF	Fax document (Imavox TurboFax)
TBK	Interactive multimedia files (Asymetrix Toolbook)
TBK	Memo backup file (dBase IV)
TBK	Memo backup file (Microsoft FoxPro)
TBK	Toolbook file (Asymetrix Toolbook)
TBL	Graphics (Native format) (Pagemaker TableEditor)
TBL	Table of values (OS/2)
TBS	Text elements (Microsoft Word for Windows)
TBX	Table (Project Scheduler 4)
TC	Configuration file (Turbo C)
TC	Configuration file (Borland C++)
TCH	Turbo C Help file (Borland C++)
TCL	Script in the TCL/TK Language
TCW	Drawing file (TurboCAD for Windows)
TD	Configuration file (Turbo Debugger for DOS)
TD0	Disk image file (Teledisk)
TD2	Configuration file (Turbo Debugger for WIN32)
TD4	Saved track design (Roller Coaster Tycoon)
TDB	Database file (Thumbs Plus)
TDB	Database file (TACT)
TDDD	A file format use by the Imagine & Turbo Silver ray-tracers
TDF	Font file (TheDraw)
TDF	Typeface definition file (Speedo)
TDH	Help file (Turbo Debugger0
TDK	Keystroke recording file (Turbo Debugger)
TDS	Symbol table (Turbo Debugger)
TDW	Configuration file (Turbo Debugger for Windows)
TEF	Fax document (Relisys TEFAX)
TEL	Hostfile (Telnet)
TEM	Turbo Editor Macro Language script (Borland C++)
TEM	Input template (IconAuthor)
TEX	Texture file
TEX	TEX text file (Scientific Word)
TEX	Datasheet file (Idealist)
TF	Configuration file (Turbo Profiler)
TFA	Area file (Turbo Profiler)
TFC	Catalogue file (Tobi's Floppy Disk Cataloguer)
TFH	Help file (Turbo Profiler)
TFM	Form file (Form Tool Gold)
TFM	TeX font metrics file (TeX)
TFM	Tagged font metric file (TeX)
TFMX	Audio file (Final Musicsystem eXtended) (Amiga)
TFS	Statistics file (Turbo Profiler)
TFW	Spatial location file used to create coordinates in TIFF image files, (Commonly used in Image mapping programs)
TG1	Project file (On Target)
TGA	Targa bitmap (Adobe Acrobat,TrueVision)
TGA	Targa bitmap (Countour Mortgage Loan Format)
TGA	Winpoint Loan file (Microsoft Excel)
TGQ	Movie file (Dungeon Keeper 2) (Bullfrog Software)
TGV	Video file (Electronic Arts) (Need for Speed I/II/III, NBA '96)
TGZ	Gzip/Tape archive (Unix)
THEME	Desktop theme (Microsoft Windows 9.x)
THM	Thumbnail image file (Microsoft Clip Gallery v.1.x)
THN	Thumbnail (Graphics Workshop for Windows)
THS	Thesaurus dictionary (Microsoft WordPerfect for Windows)
TIF	Tag image bitmap file (TIFF)
TIFF	Tag image bitmap file (TIFF)
TIG	Map file (Tiger) (Used by the US Government to distribute Map files)
TIL	Fuzzy Logic knowledge base file (Togai InfraLogic Fuzzy-C Compiler)
TIM	Texture/Image file (Playstation)
TIS	Tile set (MahJongg 3.0)
TJF	backup files (VAXTPU Editor)
TLB	OLE type library files (Microsoft)
TLB	Reference table (Bubble Editor)
TLB	Text library (VAX)
TLB	Type library (Visual C++)
TLC	Compiled tool command language source code file (Swat)
TLE	Two-Line element set (NASA)
TLP	Project timeline file (Microsoft Project)
TLX	Data file (Trellix)
TMF	Tagged font metric file (Microsoft WordPerfect for Windows)
TMO	Ztg global optimizer default optimizer file (Zortech C++)
TMP	Temporary file (Microsoft Windows) (ALL)
TMS	Script file (Telemate)
TNV	Data file (BitWare)
TOC	Table of contents file (Eudora Mailbox)
TOL	Image file (Kodak Photo Enhancer)
TOS	The Operation System for Atari line of 16/32 and 32/32 computers
TOS	Self-Extracting archive (Atari ST)
TP	Configuration file (Turbo Pascal)
TP	Sesson-state file (Turbo Profiler)
TP4	Saved picture file (Roller Coaster Tycoon)
TPB	Downloadable PCL Soft font file backup (HiJaak)
TPF	Downloadable PCL Soft font file (HiJaak)
TPH	Help file (Turbo Pascal)
TPL	Residents units library (Turbo Pascal)
TPL	Template file ( Cakewalk Audio)
TPL	Template file (Harvard Graphics 2.0)
TPL	Template file (DataCAD)
TPL	Encrypted lesson file (TutorPro)
TPP	Project file (Teleport Pro)
TPP	Protected mode units (Borland Pascal 7.0)
TPS	Database file (TopSpeed)
	
TPU	Turbo Pascal Unit (Turbo Pascal)(BGI)
TPU	Command file (VAXTPU Editor)
TPV	Packed graphics file (TutorPro)
TPW	Session-state file (Turbo Profiler for Microsoft Windows)
TPW	Packed wave files (TutorPro)
TPW	Turbo Pascal Unit (BGI) (Turbo Pascal for Windows 9.x)
TPX	Image file (ULead Photo Express)
TPZ	Compressed archive (TAR)
TPZ	Compressed archive (GNUzip)
TP3	Template file (Harvard Graphics)
TR	Session-state settings (Turbo Charge Debugger for DOS)
TR2	Session-state settings (Turbo Charge Debugger for Win32)
TRA	Saved game file (Coaster)
TRC	Debug support file (Power CTrace)
TRE	Directory tree file (PC-Tools)
TRK	Script file (Kermit)
TRM	Terminal file (Generic)
TRM	Terminal settings file (Microsoft Windows 3.x)
TRN	Translation support file (Quattro Pro)
TRN	Project usage log (MKS Source Integrity)
TRS	Executable file (MicroGraphix)
TRW	Session-state settings (Turbo Debugger for Windows)
TST	Printer test file (Microsoft WordPerfect for Windows)
TTF	TrueType font (Generic)
TTK	Translation tool kit file (Corel Catalyst)
TTO	Client access data specification file (AS/400) (Server to Client)
TUV	Tutorial file (Many programs use this suffix for their tutorials) (Generic)
TV	Table view settings (Paradox)
TV1	Overflow file above insert point in document 1 (Microsoft WordPerfect for Windows)
TV2	Overflow file above insert point in document 2 (Microsoft WordPerfect for Windows)
TV3	Overflow file above insert point in document 3 (Microsoft WordPerfect for Windows)
TV4	Overflow file above insert point in document 4 (Microsoft WordPerfect for Windows)
TV5	Overflow file above insert point in document 5 (Microsoft WordPerfect for Windows)
TV6	Overflow file above insert point in document 6 (Microsoft WordPerfect for Windows)
TV7	Overflow file above insert point in document 7 (Microsoft WordPerfect for Windows)
TV8	Overflow file above insert point in document 8 (Microsoft WordPerfect for Windows)
TV9	Overflow file above insert point in document 9 (Microsoft WordPerfect for Windows)
TVF	Table view settings (dBase IV)
TWF	Data file (TABWorks)
TWW	Template file (TagWrite)
TX8	MS-DOS text
TXB	Encoded briefing file (Descent/D2)
TXF	Compressed archive (TAR)
TXF	Compressed archive (FREEZE)
TXF	Tax exchange format (Quicken and others)
TXI	Support file (TeX)
TXT	ASCII text-formatted audio data
TXW	Wave file (Yamaha TX16W)
TYM	Time Stamp files (PageMaker 4.0)
TZ	Old compression file (TAR), (COMPRESS)
TZB	Compressed archive (Tar)
T2T	Modeling software file (Sonata CAD)
T44	Temporary file for sorting index (dBase IV)
T64	Emulator tape image file (Commodore 64)

U 
UAP	User agent profile (Used by wireless telephony applications)
UB	Raw unsigned byte (8-bit) data
UC2	Compressed archive (UltraCompressor II)
UCN	New compressed archive (UltraCompressor II)
UDF	Unique Database (Microsoft Windows NT)
UDF	Image filter (Photostyler)
UDW	Raw unsigned doubleword (32-bit) data
UE2	Encrypted archive (UltraCompressor II)
UFO	Object file (Ulead)
UG	Drawing file (AutoCAD and others)
UHS	Binary file (Universal Hint System)
UI	Espire source code (Geoworks UI Compiler)
UI	User interface file (Sprint)
UIF	Long prompts for Microsoft Windows ((Microsoft WordPerfect for Windows)
UIH	Espire header file (Geoworks UI Compiler)
UL	Audio file (ULAW)
ULAW	(CCITT G.711) audio (US Telephony)
ULD	Uploaded file information (Procomm Plus)
ULT	Music module (MOD) (UltraTracker)
UMB	Backup file (archive) (MemMaker)
UNI	UniMod music module (MOD) (MikMod)
UNI	Datafile (Forcast Pro)
UNX	Text file (Unix specific information)
UPD	Updated program data (Generic)
UPD	Universal print driver (developed as a cross-platform print driver to replace the 3,000 or so current print drivers)
UPD	Updated program data (dBase)
UPI	Program file (ULead Photo Impact)
UPO	Compiled updated datafile (dBase)
UPX	Saved Image file (ULead Photo Express)
URF	Universal radar format (Radar ViewPoint)
URL	Internet shortcut file (Universal Resource Locator)
USE	Source Integrity file (MKS)
USP	Printer font w/updated USACII extended character set (Pagemaker)
USR	User database file (Procomm Plus)
USR	Audit trail file (Pro/Engineer)
USR	User database file (Turbo C++)
USR	User database file (Tour)
UU	UU-encoded file
UU	Compressed ASCII archive (UUDE/ENCODE)
UUE	Executable compressed ASCII archive (UUDE/ENCODE)
UUE	UU-encoded file
UW	Raw unsigned 16-bit) datafile (Word)
UWF	Wave file (UltraTracker)

V 
V	Consistency check support file (ReaGeniX Code Generator)
V	Main image input file (Vivid 2.0)
VAL	Validity checks/referential integrity checks (Paradox for Windows)
VAL	Values list object file (dBase Application Generator)
VAL	Asset management document (Milliplex OmniValue)
VAN	Animation file (VistaPro)
VAP	Annotated speech file (Generic)
VAR	Variable file (IconAuthor)
VAR	ASCII text file for data dictionary (Sterling Software Groundworks, COOL Business Team Enterprise Model)
VBA	VBase file
VBP	Project file (Microsoft Visual Basic)
VBR	Remote automated registration file (Microsoft Visual Basic)
VBS	Script file (Microsoft Visual Basic)
VBW	Workspace file (Microsoft Visual Basic)
VBX	Custom control file (Microsoft Visual Basic)
VBX	Visual basic extension (Microsoft Visual Basic)
VC	Include file with color definitions (Vivid 2.0)
VC	Spreadsheet (VisaCalc)
VCE	Unformatted voice file (used by Cool Edit)
VCE	Unformatted voice file (Natural Microsystems) (NMS)
VCF	Virtual card file (Netscape)
VCF	Virtual card file (Many programs use this extension)
VCF	Configuration file; defines objects for use with Sense8's WorldToolKit (Vevi)
VCT	Class library (Microsoft FoxPro) (MFC)
VCW	Visual workbench information file (Microsoft Visual C++)
VCX	Class library (Microsoft FoxPro)(MFC)
VDA	Targa bitmap
VDA	Graphics image (Generic)
VDR	Drawing file (ComputerEasy Draw)
VEL	3D drawing file (CAD( (Ashlar)
VET	System file (VET antivirus)
VEW	View file (Clipper 5)
VEW	View file (Lotus Approach)
VFL	Clip art file (PrintMaster Gold)
VFM	Voting form (Voter)
VFN	Voting form for customers (VFN)
VGA	Video graphics array (Monitor type, also defines if your monitor is compliant with the new (1994) SVGA (Super Video Graphics Array) (SVGA)
VGA	Video graphics array (Font type for display on a VGA Monitor)
VGD	Visual display driver ( Generic CADD)
VGR	Graphics file (Ventura Publisher)
VI	Graphics file (Jovian Logic VI)
VI	Virtual Instrument file (National Instruments LABView)
VIC	Graphics file (Vicar)
VID	Shell monitor file (Microsoft DOS v.5)
VID	Screen device driver (Microsoft Word)
VID	Bitmap graphics (YUV12C M-Motion Frame Buffer)
VID	Bethesda video files (Terminator, Future Shock)
VIF	Khoros Visualisation image (SDSC Image Tool)
VIFF	Khoros Visualisation image (SDSC Image Tool)
VIK	Graphics Image (Viking)
VIR	File identified as a virus-infected file by Norton AntiVirus and possibly others
VIS	Graphics image file (VIS)
VIV	Streaming video file (VivoActive)
VIZ	dVS/dVISE file (Division)
VLB	Library file (Corel Ventura)
VLM	Drafting program file (Vellum, by Ashler)
VM	Virtual memory file (Geoworks)
VMC	Virtual memory configuration file (Adobe Acrobat Reader)
VMD	On-line video file (Sierra) (Torin's Passage)
VMF	Audio file (FaxWorks)
VMF	Font characteristics file (Ventura Publishing)
VML	Vector markup language (used by Microsoft Office 2000)
VMS	Text file with vms specific information
VO	Include file with object definiton (Vivid 2.0)
VOB	Encrypted video and audio files used on current DVD's (Digital Video Disk)
VOC	Audio file (Creative Labs Sound Blaster)
VOC	Audio file (Quartet)
VOF	Object folder (VZ Programmer)
VOX	Dialogic audio file coded using ADPCM
VOX	Formatted voice file (Natural Microsystems) (NMS)
VOX	Audio file (Talking Technology)
VP	Publication (Ventura Publisher)
VPG	Graphics image file (VPGraphics)
VQA	Video files (Westwood Studios)
VQE	VQ Locator file (Yamaha Sound)
VQF	VQ file (Yamaha Sound) (possible emerging standard)
VQL	VQ Locator file (Yamaha Sound)
VRF	Configuration file (Oracle 7)
VRM	Overlay file (Quattro Pro)
VRML	A VRML file
VRP	Project file (VXRexx)
VRS	Video device driver (Microsoft WordPerfect for Windows)
VS	Include file w/surface definition (Vivid 2.0)
VSD	Drawing file (flow chart or schematic)(Shapeware Visio)
VSL	Download List file (GetRight)
VSM	Simulation model (VisSim)
VSN	A Windows 9x/NT ViruSafe version file; used to keep information about all the files in a directory; when a file is accessed, information is compared with the VSN information to ensure that they match
VSP	Image sprite (SPX)
VSP	Data print file (Schedule Soft)
VSS	Stencil file (Shapeware Visio)
VSS	Smartshapes image file (Shapeware Visio)
VST	Targa bitmap (Generic)
VST	Bitmap graphic file (TrueVison Vista)
VSW	Workspace file (Shapeware Visio)
VUE	Animation file (3D Studio)
VUE	View file (dBase IV)
VUE	View file (Microsoft FoxPro)
VW	Text file (Volkswriter)
VWP	Audio MetaSound plug-in (VoxWare Audio Compression Toolkit version 2.02.61)
VWP	Audio plug-in (Voxware MetaVoice Toolkit)
VWR	File viewer (PC Tools)
VXD	Virtual device driver (Microsoft Windows 9.x)
VZN	Image file (WinVzn)
V8	8-bit audio file (CoVox)

W 
W	Word chart file (APPLAUSE)
W30	Printer font (AST TurboLaser)
W30	Printer font (Ventura Publisher)
W31	Startup file (Microsoft Windows 3.1)
W3L	W3Launch file
W44	Temporary file for Sort or Index (dBase)
WAB	Outlook file (Microsoft Outlook, Outlook Express)
WAD	Large file for Doom game containing video, player level, and other information
WAL	Texture file (Quake 2)
WAS	Script source code file (Procomm Plus Aspect)
WAV	Waveform sound (Microsoft Windows)
WAX	Compiled script file (Procomm Plus Aspect)
WB1	Notebook (QuattroPro for Windows)
WB2	Spreadsheet (QuattroPro for Windows)
WB3	Text file (QuattroPro for Windows)
WBC	Image file (Webshots)
WBF	Batch file (Microsoft Windows 9.x)
WBK	Backup file (Microsoft Word for Windows)
WBL	Upload file (Argo Webload II)
WBR	WordBar File (Crick Software)
WBT	Batch file (WinBatch)
WBT	Wordbar template (Crick Software)
WCD	Macro token list file (Microsoft WordPerfect for Windows)
WCM	Macro (Microsoft WordPerfect fdor Windows)
WCM	Data transmission file (Microsoft Works)
WCP	Product information description file (Microsoft WordPerfect for Windows)
WD2	Database file (Info Select) by (Micro Logic)
WDB	Database file (Microsoft Works)
WDF	WebArt data file (database file that can be converted for use in many programs)
WDG	Warftpd remote daemon file
WEB	Web document (Corel Zara)
WEB	Web source code file
WFB	Bank file (Maui/Rio/Monterey) (Turtle Beack WaveFront)
WFD	Drum set (Maui/Rio/Monterey)(Turtle Beach WaveFront)
WFD	Audio waveform (WaveForm Manager Pro)
WFL	Flowchart file (Winflow)
WFM	Windows form (Virtual dBase)
WFN	Symbol (Corel Draw)
WFP	Program file (Turtle Beach WaveFront)(Maui/Rio/Monterey)
WFT	Data file (NICOLET (Old Format), see NRF)
WFX	Data file (WinFax)
WG1	Worksheet (Lotus 1-2-3/G)
WG2	Worksheet (Lotus 1-2-3 for O/S2)
WGP	Data file (Wild Board Games)
WI	Wavelet compressed bitmap (Corel)
WID	Width table (Ventura Publisher)
WIF	Wavelet image file (see WI)
WIL	WinImage file
WIM	Wireless identity module (Used by wireless application protocols)
WIN	Window file (Microsoft FoxPro)
WIN	Window file (dBase)
WIN	Window preference file (Pro/Engineer)
WIS	Script file (Reynolds & Reynolds) (Stores the results of a database query)
WIZ	Wizard file (Microsoft Word)
WIZ	Page wizard (Microsoft Publisher)
WK1	Spreadsheet (Lotus 1-2-3 v. 1 and 2)
WK3	Spreadsheet (Lotus 1-2-3 v. 3)
WK4	Spreadsheet (Lotus 1-2-3 v. 4)
WKB	Document file (Microsoft WordPerfect for Windows)
WKE	Spreadsheet (Lotus 1-2-3 Educational version)
WKQ	Spreadsheet (Quattro Pro)
WKS	Spreadsheet (Symphony 1.0)
WKS	Worksheet spreadsheet (Lotus 1-2-3)
WKS	Document (Microsoft Works)
WKS	Workspace file (Xlisp)
WLD	REND386/AVRIL file
WLF	Upload file (Argo Upload I)
WLK	Graphics file (Virtus Walkthrough)
WLL	Add-In file (Microsoft)
WMA	Audio file in Microsoft Windows Media format (Can be changed to ASF) Siren (Sonic Foundry)
WMC	Backup files for startup (MathCAD for Windows)
WMC	Macro file (Microsoft WordPerfect for Windows)
WMC	Text file (WordMARC)
WMF	Metafile (Microsoft Windows)
WN	Text file (NeXT WriteNow)
WNF	Outline font description file (CorelDRAW)
WOA	Swap file (Microsoft Windows 3.x)
WOC	Organization chart (Microsoft Windows OrgChart)
WOW	Music module (MOD) (Grave Composer)
WP	Document file (Microsoft WordPerfect for Windows)
WPA	Word processor document (ACT!)
WP4	Document (Microsoft WordPerfect for Windows 4.0)
WP5	Document (Microsoft WordPerfect for Windows 5.0)
WP6	Document (Microsoft WordPerfect for Windows 6.0)
WPD	Demo file (Microsoft WordPerfect for Windows) (ALL)
WPD	Document (Microsoft WordPerfect for Windows)
WPF	Document (Enable)
WPF	Fax document (WorldPort)
WPF	Form file (Microsoft WordPerfect for Windows)
WPG	Microsoft Word for Windows vector graphics (DrawPerfect)
WPG	Graphics file (Microsoft Word for Windows)
WPK	Macro (Microsoft Word for Windows)
WPM	Macro (Microsoft Word for Windows)
WPS	Text document (Microsoft Works)
WPT	Template (Microsoft Word for Windows)
WPW	PerfectWorks document (Novell)
WQ!	Compressed spreadsheet (QuattroPro)
WQ1	Spreadsheet (QuattroPro/DOS)
WQ2	Spreadsheet (QuattroPro version 5)
WR1	Symphony file (Lotus)
WR1	Spreadsheet (Symphony 1.1-2)
WRD	Template (Charisma)
WRG	ReGet document
WRI	Write document (Windows Write)
WRK	Project file (CakeWalk Music Audio)
WRK	Spreadsheet (Symphony 1.0)
WRL	Virtual Reality model
WRP	Compressed Amiga archive (WARP)
WRP	3D modeling file (Raindrop Geomagic) (Scandata)
WRS	Resource file (Microsoft Word for Windows)
WRZ	Another VRML fileject
WS	Text file (WordStar)
WS1	Document (WordStar for Windows version 1)
WS2	Document (WordStar for Windows version 2)
WS3	Document (WordStar for Windows version 3)
WS4	Document (WordStar for Windows version 4)
WS5	Document (WordStar for Windows version 5)
WS6	Document (WordStar for Windows version 6)
WS7	Document (WordStar for Windows version 7)
WSD	Document (WordStar for Windows 2000)
WSP	WorkSpace file (Fortran PowerStation)
WST	Document (WordStar for Windows)
WSZ	Skin (WinAmp)
WTA	Used by wireless telephony applications
WVL	Wavelet Compressed Bitmap
WVW	Interleaf WorldView format (a PDF format)
WWB	Button bar for document window (Microsoft WordPerfect for Windows)
WWK	Keyboard layout file (Microsoft WordPerfect for Windows)
WWL	Add-in file (Microsoft Word)
WXB	Backup document file (EXP: The Scientific Word Processor
WXD	Music resource file (Relic Entertainment)(Home World)
WXP	Document file (EXP: The Scientific Word Processor)

X 
X	AVS image (SDSC Image Tool)
X	Source code file (Lex)
XA0	Dos help file (Xtree)
XAR	Corel Xara drawing
XBM	A MIME 'X11" bitmap image
XB0	Dos help file (Xtree)
XC0	Dos help file (Xtree)
XDL	XML Schema file
XD0	Dos help file (Xtree)
XDR	XML data reduced file
XE0	Dos help file
XFN	Printer font file (Xerox)
XFN	Printer font file (Ventura Publisher)
XFT	Printer font file (24 Pin) (ChiWriter)
XFX	Fax Document (Various)
XHTML	eXtensible hypertext markup language
XI	Instrument sample file (ScreamTracker)
XI	Instrument file (FastTracker II)
XIF	Wang imaging file (Included with Windows 95)
XIF	Image file (Xerox) (same as TIF)
XIF	Image file (Pagis)
XIF	Image file eXtended (ScanSoft) the file is similar to TIFF and is a (Pagis) native format
XLA	Add-in file (Microsoft Excel)
XLA	Archive (Xlib)
XLB	Toolbar file (Microsoft Excel)
XLB	Datafile (Microsoft Excel)
XLC	Chart file (Microsoft Excel)
XLD	Dialogue file (Microsoft Excel)
XLK	Backup file (Microsoft Excel)
XLL	Add-in file (Microsoft Excel)
XLL	Dynamic link library (Microsoft Excel)
XLM	Macro file (Microsoft Excel)
XLS	Worksheet file (Microsoft Excel)
XLT	Template file (Microsoft Excel)
XLT	Translation table (Lotus 1-2-3)
XLT	Translation table (Symphony)
XLT	Translation table (Procomm Plus)
XLV	VBA module (Microsoft Excel)
XLW	Workbook (Microsoft Excel)
XM	Music module (MOD) (Fast Tracker 2)
XMI	Compressed midi music (eXtended)
XML	eXtensible markup language
XML	General XML instance document
XNF	Network file (Standard)
XNK	Shortcut file (Microsoft Exchange)
XOF	Image file (Render Morphics)
XON	Datafile (Axon)
XPM	X BitMap format
XQT	Executable file (Waffle)
XQT	Macro file (SuperCalc)
XXX	XXXX
XR1	Data file (Epic Megagames Xargon)
XRF	Cross-reference file (Generic)
XSD	XML schema description file
XTB	External translation table (LocoScript)
XTP	Data file (Xtree)
XWD	X Window Dump format (SDSC Image Tool)
XWF	Works file (Yamaha XG) (MIDI sequencing)
XWK	Keyboard mapping file (Crosstalk)
XWP	Session file (Crosstalk)
XWP	Text file (Xerox Writer)
XX	Compressed ASCII archive (XXENCODE)
XXE	Compressed ASCII archive (XXENCODE)
XY	Text file (XYWrite)
XY3	Document file (XYWrite III)
XY4	Document file (XYWrite IV)
XYP	Document file (XYWrite III Plus)
XYW	Document file (XYWrite for Windows 4.x)
X01	Secondary index file (Paradox)
X02	Secondary index file (Paradox)
X03	Secondary index file (Paradox)
X04	Secondary index file (Paradox)
X05	Secondary index file (Paradox)
X06	Secondary index file (Paradox)
X07	Secondary index file (Paradox)
X08	Secondary index file (Paradox)
X09	Secondary index file (Paradox)
X10	Dos help file (Xtree)
X16	Macromedia Extra (program extension), 16 bit
X20	Dos help file (Xtree)
X30	Dos help file (Xtree)
X32	Macromedia Extra (program extension), 32 bit
X40	Dos help file (Xtree)
X50	Dos help file (Xtree)
X60	Dos help file (Xtree)
X70	Dos help file (Xtree)
X80	Dos help file (Xtree)
X90	Dos help file (Xtree)

Y 
Y	Grammar file (Yaac)
Y	Compressed Amiga archive (YABBA)
YAL	Clipart library (Arts & Letters)
YBK	Yearbook file (Microsoft Encarta)
YUV	Graphics file (YUV)
YZ	Compressed file archive (YAC)
Y01	Secondary index file (Paradox)
Y02	Secondary index file (Paradox)
Y03	Secondary index file (Paradox)
Y04	Secondary index file (Paradox)
Y05	Secondary index file (Paradox)
Y06	Secondary index file (Paradox)
Y07	Secondary index file (Paradox)
Y08	Secondary index file (Paradox)
Y09	Secondary index file (Paradox)
 
Z 
Z	Compressed ASCII archive (COMPRESS)
Z	Unix file	Compressed
ZAP	Software installation settings file (Microsoft Windows)	
ZAP	Compressed file (FileWrangler)	
ZDG	Compressed text document (Zview)	
ZER	Data file (Zerberus)	
ZFS	Assembler source code file (C,C++)	
ZGM	Graphics file (ZenoGraphics)	
ZIP	Zip file	Compressed archive
ZOM	Compressed Amiga archive (ZOOM)	
ZOO	An early compressed file format	
ZVD	Voice file (Zyxel Z-Fax)	
Z3	Game module (Infocom)	
 
NNumbers and symbols 
###	Temporary file (used with QTIC)
0	Compressed data file (Microsoft Dos DoubleSpace)
0B	Extended character set linedraw printer font (PageMaker)
000	Data file (GEOWorks)
000-20009	Used to number old (backup) versions of files (for example, CONFIG.SYS when changed by an installation program); also used to number related data files for multiple users of a small-scale PC application
000	Data file (Compressed), (Microsoft Dos DoubleSpace)
001	Fax data file (Hayes compatible, and others)
075	75x75 pixel (DPI) display font (Ventura Publisher)
085	85x85 pixel (DPI) display font (Ventura Publisher)
091	91x91 Pixel (DPI) display font (Ventura Publisher)
096	96x96 pixel (DPI) display font (Ventura Publisher)
286	Virtual device driver (VXD), (Microsoft Windows)
2GR	Graphics driver (VGA),(Microsoft Windows Video Grabber)
1ST	Documenting wizard list (Microsoft Visual FoxPro)
001-999	Database index files used by (Superbase)
8	Source file (Assembly) (Similar to Microsoft Assembler)
113	Backup data file (Iomega Backup)
12M	Smartmaster file (Lotus 1-2-3 '97)
12U	Font file (PI font set), (Adobe PageMaker)
123	Lotus 1-2-3, '97 data file
1-STEP	Backup file (Iomega Backup)
10X	Bitmap graphics file (Gemini 10X printer file)
2D	Two-dimensional drawing file (VersaCAD)	http://www.versacad.com/vcadhome.htm
2GR and 3GR	VGA Graphics driver/configuration files (Microsoft Windows)	
24B	Graphic file (24 bit bitmap)	
3D	Three-dimensional drawing file (VersaCAD)	http://www.versacad.com/vcadhome.htm
3DM	3D NURBS modeler, (Rhino)	
3DS	A file in 3D Studio (for DOS) format	
386	A file for use in an 80386 or higher microprocessor	
411	Data file (Used by digital cameras)	
4GE	Compiled code (Informix 4GL)	
4GL	Source code (Informix 4GL)	
4V	Music file (Quartet)	
669	Music mod file (Composer 669)(Unis Composer)	
669	Tracker module (Composer 669)	
#IB	Data file for dot matrix printer (LocoScript)	
#01 and higher	A method of numbering picture files for a roll of film that has been scanned for computer presentation	
#24	Data file for 24 pin dot matrix printer (Locoscript)	
#SC	Data file for dot matrix printer (used by LocoScript)	
#ST	Standard Mode dot matrix printer definition file (LocoScript)	
$ED	Temporary editor file (Microsoft C, C++)	
$D$	Data file (used by Planner),(OS/2)	
$DB	Temporary data file (dBASE IV)	
$LN	Response file created by TLink (Borland C++)	
$$F	Database file (used by OS/2)	
$$P	Text file (OS/2)	
$$S	Generic OS/2 Spreadsheet file	
$$$	Used by OS/2 to keep track of archived files	
$$$	Generic Temporary file	
$VM	Temporary file (Microsoft Windows Virtual Manager 3.11)	
~PR	Project backup file (Terramodel)	
~$~	Temporary file (1ST Reader)	
~AP	AppExpert project database file (Borland C++ 4.5)	
~DE	Project backup file (Borland C++ 4.5)	
~MN	Menu backup (Norton Commander)	
@@@	Screen files used in the installation and instruction on use of such applications as Microsoft Codeview for C