Using Commas

Commas are one of the most essential punctuation marks in writing, but figuring out when to use them can be difficult. Here’s a guide to help you remember when to use a comma.


  • Commas help to clarify the meaning in sentences.
    - INCORRECT: Let’s eat Grandpa!
    - CORRECT: Let’s eat, Grandpa!
  • Commas also make lists easier to read.
    - INCORRECT: This recipe requires milk eggs and cheese.
    - CORRECT: This recipe requires milk, eggs, and cheese. 

Use a comma

  • After an introductory phrase that precedes the main clause of a sentence
    - Before Jack left the house, he locked the door behind him.
  • With a coordinating conjunction (remember FANBOYS: for, and, nor, but, or, yet, so) in order to combine two independent clauses
    - Carol had no flour, so she couldn’t bake cookies.
  • Between items in a series or list
    - My favorite colors are red, purple, and blue.
  • To set off clauses, phrases, or words that add nonessential information to the sentence
    - My necklace, which my grandma gave me, fell down the garbage disposal.
  • In dates, addresses, titles, names, and numbers
    - This overdue library book was due October 12, 2013.
  • To set off quotations
    - Franklin Delano Roosevelt said, “The only thing we have to fear is fear itself.”

Source: Hacker, Diana. A Writer’s Reference. Boston: Bedford, 1995.