Unit (abbreviation)

Definition

Imperial Value

1 second (s)

Base unit of time. In the International System, the second is defined as the duration of 9 192 631 770 cycles of radiation corresponding to the transition between two hyperfine levels of the ground state of cesium 133.

1 second

1 meter (m)

Base unit of length defined as the distance traveled by light in a vacuum during 1/299 792 458 of a second.

39 & 47/127 inches exactly (1 & 107/1 143 yards exactly)

1 are (a)

Base unit of area defined as 1 square meter.

1.196 square yards

1 liter (L)**

Base unit of capacity defined as 1/1 000 cubic meter.

33 & 385 176 391/473 176 customary fluid ounces exactly (35 & 88 685/454 609 imperial fluid ounces exactly)

1 kilogram (kg)

Base unit of mass; defined as the standard kilogram, a platinum-iridium bar in the custody of the International Bureau of Weights and Measures (BIPM) near Paris, France.

2 & 92 815 260 000/453 592 370 000 avoirdupois pounds exactly.

Base (meters)

Unit Name (abbreviation)

Customary/Imperial Equivalent (inches, miles)

0.000 000 000 1 m

1 angstrom

1/254 000 000 in.

0.000 001 m

1 micrometer (µm)

0.000 039 37 in.

0.001 m

1 millimeter (mm)

0.039 37 in.

0.01 m

1 centimeter (cm)

0.393 7 in.

0.1 m

1 decimeter (dm)

3.037 in.

1 m

1 meter (m)

39.37 in.

1 000 m

1 kilometer (km)

39 370 in. (0.621 mi.)

150 000 000 000 m

1 astronomical unit

93 000 000 mi.

9 454 254 955 488 000 m

1 lightyear

5 874 601 673 407.3 mi.

30 915 413 704 445 760 m

1 parsec

19 209 947 472 041.9 mi.

Base (meters)

Unit Name (abbreviation)

Customary/Imperial Equivalent

0.01 m x 0.01m

1 square centimeter (cm²)

0.154 9 square inches

1 m x 1 m

1 square meter (1 are) (m², a)

1.196 square yards

100 m x 100 m

1 hectare (ha)

2.47 acres

1 000 m x 1 000 m

1 square kilometer (km²)

247 acres (0.386 square miles)

Base (meters)

Unit Name (abbreviation)

Customary/Imperial Equivalent

0.01 m x 0.01 m x 0.01 m

1 cubic centimeter (cm³)

0.061 cubic inch

1 m x 1 m x 1 m

1 cubic meter (m³)

1.308 cubic yards

Base (cubic meters)

Unit Name (abbreviation)

Customary Equivalent

Imperial Equivalent

0.000 001 m³

1 milliliter (mL)

0.033 8 fluid ounces

0.035 2 fluid ounces

0.001 m³

1 liter (L)

0.264 2 gallon

0.219 9 gallon

Base (grams)

Unit Name (abbreviation)

Customary/Imperial Equivalent (avoirdupois)

0.000 001 g

1 microgram (µg)

0.000 015 43 grains

0.001 g

1 milligram (mg)

0.000 035 27 ounce

1 g

1 gram (g)*

0.035 273 ounce

1 000 g

1 kilogram (kg)

2.204 6 pounds

1 000 000 g

1 megagram (Mg), more commonly:

1 metric ton (t)

1.102 3 short tons/

0.984 2 long ton

Prefix

Symbol

Scientific Notation

Ordinary Notation

U.S. Name

yocto-

y

x10^-24

0.000 000 000 000 000 000 000 001

zepto-

z

x10^-21

0.000 000 000 000 000 000 001

atto-

a

x10^-18

0.000 000 000 000 000 001

femto-

f

x10^-15

0.000 000 000 000 001

pico-

p

x10^-12

0.000 000 000 001

trillionth

nano-

n

x10^-9

0.000 000 001

billionth

micro-

µ

x10^-6

0.000 001

millionth

milli-

m

x10^-3

0.001

thousandth

centi-

c

x10^-2

0.01

hundredth

deci-

d

x10^-1

0.1

tenth

x10⁰

1

one

deka-

da

x10¹

10

ten

hecto-

h

x10²

100

hundred

kilo-

k

x10³

1 000

thousand

mega-

M

x10⁶

1 000 000

million

giga-

G

x10⁹

1 000 000 000

billion

tera-

T

x10¹²

1 000 000 000 000

trillion

peta-

P

x10¹⁵

1 000 000 000 000 000

exa-

E

x10¹⁸

1 000 000 000 000 000 000

zetta-

Z

x10²¹

1 000 000 000 000 000 000 000

yotta-

Y

x10²⁴

1 000 000 000 000 000 000 000 000