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Center For Academic Excellence

CAE | Commas

Commas, as other marks of punctuation, guide the reader. There are many rules for comma use, and they change because language use is dynamic, never static. Currently, then the following rules will help you be a more effective writer.

1. Use commas to separate three or more items in a series.

Frequently the comma is omitted after the next-to-last item in newspapers or magazines, but you are always correct to add the last comma. In fact, the comma
often prevents misreading.

Example: I will be so glad when this semester is over; I am taking biology, physics, calculus, and advanced chemistry.

2. Use commas between coordinate adjectives.

Adjectives are coordinate when each adjective modifies the noun separately. Their order can be reversed, and the word and can be inserted between them.
They, also, are adjectives that do not give information about size, shape, age, color, nationality, or religion.

Example: I will choose a kind, compassionate, and wise woman as my new physician.

3. Use a comma to set off parenthetical expression.

A parenthetical expression is one that is read almost like an aside to the reader. It gives additional, extra information.

I, on the other hand, failed gross anatomy.

4. Use a comma to set off nouns of direct address.

Direct address simply means that a person is called by his or her name.

Please, Harriette, don’t forget that your best friend still needs you even though she has moved many miles away.

5. Use a comma to set off contrasting elements.

Generally, a contrasting element is introduced by such words as not, unlike, never.

Example: I knew then that I was going to be a nurse, not a teacher.

6. Use a comma to set off the text that identifies the speaker from the direct quotation.

Example: “This is the hardest course I have ever had,” Steve wrote to his parents.

7. Use a comma in dates, addresses, long numbers and titles.

If only the month and the year are given, no comma is necessary.

On July 1, 1997, the Center for Academic Excellence opened.

Please send this letter to Rachel Sommers at 120 Loblolly Avenue, Asheville, North Carolina.


Gilbert Bradham, M.D., is the Dean of Students at the Medical University of South Carolina.

8. Use a comma to prevent misreading when a word is omitted, repeated, or could be mistakenly grouped with the words that follow.

This rule does give the writer some leeway in deciding where to place commas, but the comma can be used only if the reader might misunderstand the sentence without it. It is a rarely used rule.

If you say you are ready to dance, dance.

Please note that this handout should be used in conjunction with other handouts on commas:

  • Punctuating compound-complex sentence
  • Comma Use with Introductory Material
  • Comma Use with Nonrestrictive Material

Developed by
Jennie Ariail, Ph.D. - Director
Tom Waldrep, Ph.D. - Director (retired)

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