Use commas when needed.

 Seven ways to use commas

Correct Examples

a) When commas work like parentheses, place one comma BEFORE and one comma AFTER. 

The best author, if you like adventure, is Jack London. 

The best author (if you like adventure) is Jack London. 

Well, Susan, you are in a fine mess. 

Well (Susan) you are in a fine mess. 

Is Houston, Texas, really our fourth largest city?

Is Houston (Texas) really our fourth largest city?

b) Use a comma to separate the halves of a compound sentence that is joined with a conjunction. 

She ran upstairs, and he hid in the basement. 

c) Use a comma with multiple adjectives or adverbs if the comma could be replaced with the word “and”. 

Correct with adverbs

He quickly, suddenly touched the bomb. 

Correct with adjectives

She entered the long, dark hallway. 

d) Use a comma after an introduction to the sentence. 

If George arrives, we will leave. 

 Because George will arrive, we will leave too. 

Whenever George arrives, we will leave. 

 After George arrives, we will leave. 

 While George is gone, we will wait. 

e) Place a comma between a direct quote and words that identify the speaker. 

Speaker after the quote:

“Please come,” he said.

Speaker before the quote:

He said, “Please come.”

f) Use commas to separate three or more items in a list.  Use a conjunction before the last item. 

Once there were four children named Peter, Susan, Edmund, and Lucy.

She can read White Fang, Treasure Island, or Ben Hur

g) When additional information appears at the end of the sentence, use a comma to separate it from the main part of the sentence.  The information must be additional ­– not something essential to understanding the sentence. 

Correct Example with a participle phrase:

They had us in a bad spot, taking us out one at a time. 

Correct Example with an appositive:

He hired Johnson, a mercenary.