10 Rules for Using Commas

  1. Use commas to separate independent clauses when they are joined by: and, but, or, nor, and sometimes yet.
    The game was over, but the crowd refused to leave. Correct
    The game was over but the crowd refused to leave. Run on
    The game was over, the crowd refused to leave. Comma Splice
  2. Use commas to separate two or more coordinate adjectives. (Coordinate adjectives describe the same noun.)
    The noisy, enthusiastic group applauded the speech.
    BUT -The new tennis courts will be open soon.
  3. Use commas to separate words, phrases, and clauses written in a series of three or more.
    A trio of Marie, Ellen, and Frances sang at the follies.
    Jack walked into my office, took off his hat, and sat down.
    BUT - DO NOT separate two verbs which follow the same subject.
    John ran out of the house and leaped into the air.
  4. Use commas at the beginning of a sentence after an introductory clause or phrase which has a verb or verb form.
    Hearing his owner call him, the dog ran forward.
    While I was reading, the cat scratched at the door.
    If you want a seat, you ought to arrive early.
  5. Use commas at the beginning of a sentences to set off exclamations and comments such as “yes,” “no,” “well,” “oh,” “golly gee,” and “darn.”
    Darn, my grandma ate my homework.
  6. Use commas in the middle of the sentence to set off phrases and clauses which are nonessential. Use these commas in pairs.
    Sarah Clark, who lives on my street, is in my biology class.
    BUT -The girl who is sitting at the table next to you is in my biology class.

    Three Uses:

    Nonessential appositives: Tom, the captain of the team, was injured in the game.
    Names in direct address: It is up to you, Jane, to do your homework.
    Nonessential comments: I was, however, too tired to make the trip.
  7. Use commas at the end of the sentence to separate sharply contrasted, coordinate elements.
    He was merely ignorant, not stupid.
    The rain was soft, yet continuous.
  8. Use commas to set off all geographical names, items in dates (except month and day), addresses (except street name and number, and titles in names.
    Birmingham, Alabama, gets its name from Birmingham, England.
    July 22, 1978, was a momentous day in his life.
    Who lives at 1600 Pennsylvania Avenue, Washington, D. C. 67676?
    Donald B. Lake, Ph.D., will be the speaker.
  9. Use commas after “he said” or “she said” (and others) to set off direct quotation.
    John said, “I’ll see you tomorrow.”
    “I was able,” she answered, “to complete the assignment.”
  10. Use commas to prevent possible confusion and misreading.
    Above, the mountains rose like purple shadows.
    To John, Harrison had been sort of an idol.