How do I know when I need to use a comma?

Commas are the most used and misused punctuation for beginning college writers. Generally, the comma is used to signal and pause. Commas help to make a sentence’s meaning clearer, but if used carelessly, can cloud the meaning entirely. The most important rule to follow for using a comma is: use a comma only when you are sure you need it. More specifically, if you follow these six rules, you will use commas correctly.

1. Put a comma before a coordinating conjunction when it connects two independent clauses.

Our plane was late, so we ate dinner.

2. Put a comma between items in a series and coordinate adjectives.

I’m taking math, science, and reading.

Use the large, red pen.

Some words seem to go togther, so do not need a comma:

She is a sweet little old lady.

3. Put a comma after an introductory expression (word clause, phrase) that does not flow smoothly into the sentence.

Yes, I have visited New York City.

Although I like reading, I watched a movie instead.

For example, dogs might be a better choice than hampsters.

4. Put commas around the name of a person being addressed (direct address).

Look, Derek, I do not care for your attitude.

Kim, would you hand me that piano?

Would you get me a Coke, darling?

5. Put commas around expressions that interrupt the flow of the sentence.

I think, of course, that she is the best person for the job.

6. Put commas around non-restrictive information, or nonessential information. If the information is removed, it will not change the meaning of the sentence.

George W. Bush, the President of the United States, will speak tonight.

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Composition FAQ