Commas, Semicolons, and Colons

When and how to use commas:

  • Commas come before coordinating conjunctions (for, and, nor, but, or, yet, so) when they link two independent clauses*:

    It was raining, and I was hurrying to get home.

    She felt terrible, but she went to class anyway. 

  • Commas separate items in a series, including coordinate adjectives:

    He bought bananas, apples, oranges, and cheese.

    She had long, dark, straight, thick hair.

  • Commas set off parenthetical elements such as an appositive, which is a noun phrase or clause that renames or describes the noun directly beside it, and nonrestrictive relative clauses:

    The Washington monument, a massive obelisk, was completed in 1884.
    My parents, who met each other in 1962, have been married for 50 years. 

  • Commas set off transitional phrases

    On the other hand, many diets decrease stamina and strength.
    As a matter of fact, American football was derived from rugby.
    Many people, however, are allergic to cats.

  • Commas follow introductory clauses and phrases:

    On the way home, I stopped to buy groceries.

    Because it was raining, I took a taxi home.

    To our surprise, they were brothers.

  • Use commas for direct address, tag questions, mild interjections, and yes/no:

    I hate to say this, John, but this relationship just isn’t working out.
    You like chocolate, don’t you?
    Well, I might have time for lunch with you next week.
    Yes, you must do the homework.

  • Commas indicate direct quoted speech: He said, “Let’s go,” and we did.

    He said we should go, and we did.

  • Commas go inside quotation marks:

    He had heard about “oleo,” but he didn’t know what it was.


When and how to use semicolons:


  • Semicolons connect two independent clauses that are closely related:

    The book is informative; it has helpful charts and graphs.

    My brother is going to Spain for the summer; he will be studying Spanish.

  • Semicolons separate three or more items in a series that already have commas in them:

    I like big, purple shirts; red, high-heeled shoes; and fluffy, yellow pillows.

    I live with Larry, a student; Moe, an executive; and Curly, a cop.

  • Semicolons separate two independent clauses that are joined by a transition word or phrase:

    It is important to get enough sleep; however, too much sleep can be bad for your health.

    Jack did not eat the leftovers in the fridge; instead, he ordered a pizza.

  • Semicolons go outside quotation marks:

    He had heard about “oleo”; he didn’t know what it was.

When and how to use colons:


  • Colons come after independent clauses and may be followed by lists, words, phrases, clauses, or independent clauses:

    Then I came to a shocking realization: He did not remember me.

    She traveled to the following countries: England, Italy, and Japan.
    He was cooking her favorite dinner: cheese fajitas with corn.

  • Colons go outside quotation marks:

    He explained “oleo”: It’s a non-dairy butter substitute.

Adapted from: The Harbrace College Handbook (12th ed.) by Horner/Webb/Miller and A Writer’s Reference (4th ed.) by Diana Hacker.