When and How to Use a Comma

Are you unsure where, how, or even when to use commas? If so, here are some helpful hints regarding these pesky punctuation marks.

Between Two Independent Clauses When Joined by a "Coordinating Conjunction"

An independent clause is a complete sentence. How do you know if a sentence is complete or not? Well, in order for it to be a sentence, there needs to be a subject and a verb. (Sentence/Independent Clause: I ate an apple. In this example, if the words "I" or "ate" were missing, it would be an incomplete sentence.) 

Sometimes, sentences are combinations of independent clauses -- in this case, we use punctuation or coordinating conjunctions (and, but, or, for, nor, so, yet) to connect them.

Use commas before connecting words (and, but, or, for, nor, so, yet) to separate clauses that could stand alone as sentences:

  • My father ran to the kitchen, and my mother answered the door.

*Note: If the separate statements cannot stand alone as sentences, then no comma is needed:

  • I swept the floor and dusted the picture frames.

After "Introductory Phrases" of Three or More Words Unless They Are Followed Immediately By a Verb:

  • Next Sunday morning, the panel of judges will announce the winner.

*Note: No comma is needed when the introductory phrase is very short or followed by a verb:

  • After dinner came dancing and singing.

To Enclose Phrases that Interrupt a Sentence:

  • Runners, especially those with shin splints, need to stretch before racing.

For Extra Information About a Person You Are Describing:

Katie, Sara’s little sister, works at Hudson’s.

When Listing Items

Use commas to separate items in a list:

  • They praised her for her kindness, generosity, and organization.

*Note: Whether to use the second comma depends on your personal preference or the style guide you use. In Associated Press (AP) style, for example, the second comma is omitted:

  • Summer sports are baseball, golf and swimming.

To Separate Direct Quotes from the Rest of the Prose:

  • “I don’t want to go,” Joe said with a sigh.
  • According to Dr. Monroe, “Zoos have decreased in popularity since 1987.”

To Separate Dates and Geographical Locations:

  • My dad was born on February 4, 1967.
  • I want to move to Bernie, Texas.

To view or print our Helpful Handout, click here: Commas

*comes with learning comic attached

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Page last modified February 14, 2019