A comma functions like yield signs, a pause to keep you from having a wreck, crashing into the words ahead.

  • Show a pause …

after an introductory phrase longer than three or four words.

  1. If you want to keep the meaning clear, pause after a long opening phrase.
  2. For short openers you might not want to pause. (No comma needed).

to separate a question from a statement.

  1. Bill is coming, isn’t he? (Notice the natural pause after “coming,” which keeps the statement from running into the question.)
  2. I can’t believe that, can you?

to separate a list of three or more items.

  1. In the pantry Johnny found the bread, peanut butter, and grape jelly. (Some style books want to leave out the comma before the conjunction, but that can be confusing.)
  2. A soldier’s favorite colors should be red, white, and blue.

in place of saying “and” between two adjectives that modify a noun.

  1. John is a kind, intelligent young man.
  2. He stared vacantly into the clear, clear blue sky. (If saying “clear and blue sky” sounds awkward to you, don’t use a comma.)

for dialogue attributions that voice the words.

  1. “I’ve got a secret,” Sammie whispered.
  2. Patty laughed, laughed. “She looks ridiculous in plaid dress.” (People don’t laugh words, they say them. The laughter needs to be a separate sentence.)

to change the sound and pace of the sentence.

  1. Timmy counted eight-nine-ten and ran to find where his friend was hiding. (Quick count, using hyphens instead of commas).
  2. Mom counted one, two, three, and Timmy jumped up from the TV and went to take his bath. (Slow count).
  • Show pauses surrounding …

an emphasized adverb.

  1. We waited, patiently, for our son to get home. (The emphasis suggests an involuntary choice.)

a phrase that doesn’t restrict what it modifies.

  1. Peter, who graduates this year, plans to join the army. (“Who graduates this year” doesn’t limit the meaning of Peter. Leave out the phrase and the sentence is still true, so a comma should be used.)
  2. A man who wishes he had a friend isn’t very friendly. (“Who wishes he had a friend” limits the identity of “the man.” Leave out the phrase and the meaning changes, so a comma should not be used.)

an interrupting phrase or word.

  1. I believe, no matter what the weather is like, we’ll have a good time.
  2. When I’m writing, honestly, I’m in another world. (Without the comas, you have to wonder what it’s like to write dishonestly.)

the name or title of someone addressed directly.

  1. Listen, Jack, you don’t have a job if you can’t get here on time.
  2. That, sir, is the whole story.

the year when it follows the month and day.

  1. On August 11, 1984, President Ronald Reagan joked about bombing Russia.
  2. Garry Kasparov faced IBM’s chess-playing computer in February 1996 and won. (Without the day, no commas are needed to set of the year.)

degrees or titles that follow names.

  1. William Henry, M.D., did the surgery.
  2. Jack Moncrief Jr built a financial empire. (“Jr” and “Sr” are now considered a part of the name. Commas and period are no longer required.)
  • Next to Quotation Marks.

Unlike colons and semicolons, which always go outside, the comma always goes inside the quotation marks.

Example: After so many days reading “How to Write,” I just needed to write.