Comma Usage

Six comma rules

In this presentation, you’ll learn six basic rules for using—and not using—commas.

There are some exceptions to these rules, but if you master these, you’ll be in good shape.

Comma rule 1

You need to use a comma whenever you’re combining two independent clauses with a

coordinating conjunction.

(Remember, the coordinating conjunctions are the FANBOYS words we reviewed

in the run-ons presentation.)

Example for rule 1

I had my essay ready at the beginning of class on Monday, but I forgot to turn it in.

Comma rule 2

You use a comma to separate three or more items in a series.

(Note: the last comma in the series is known as the “series comma” and it is optional.)

Example of rule 2

Last week we wrote in-class essays, offered peer feedback, and practiced identifying the

elements of narrative.

Comma rule 3

Use a comma after an introductory expression—even when it’s only one word—or a

comment or question tacked on at the end.

Example of rule 3

When the instructor called on me during class, I was glad I had read the assignment.

Example of rule 3

I am enjoying the novel we’re reading in class, much to my surprise.

More on rule 3

If you aren’t sure about whether or not something is an introductory expression or a tacked on comment or question, see whether or not the sentence is complete without it.

If so, use a comma.

(Some of these are optional commas, but some are required. The simplest answer is to put them in.)

Comma rule 4

Put commas before and after the name of someone you are directly addressing.

Example of rule 4

Did you know, Mr. President, many people in this country oppose your goals?

Comma rule 5

Put commas before and after expressions that interrupt the flow of the sentence.

(i.e. however, of course, I think, therefore, etc.)

Example of rule 5

I believe, as you know, everyone can master the basic writing skills.

Example of rule 5

Becoming a good writer is like becoming a concert pianist; therefore, mastering writing

requires a lot of practice.

Comma rule 6

Place commas before and after any additional information not needed in the sentence.

Example of rule 6

Brent Staples, who wrote “Black Men and Public Space,” strikes me as an honest and

generous human being.

More on rule 6

The man who wrote “Black Men and Public Space” will speak next week on campus.

Here is an example of where the “who wrote “Black Men and Public Space” cannot be

removed from the sentence, so there are no commas used.

Example of rule 6

The Loop, Nicholas Evans’s second novel, is more than a simple love story.

More on rule 6

Nicholas Evans’s novel The Loop is going to be made into a movie.

In this example, we don’t need the commas because identifying which of his novels is a

necessary part of the sentence.