Tutorial for Comma Usuage

What are they?

A comma (,) is used to separate parts of a sentence from one another. Commas, when used correctly, make your sentences clear and help readers understand your meaning.

  1. Use a comma before a coordinating word (and, but, for, nor, or, so, yet) that joins two independent clauses.

    The ball flew past the goalie, but the score did not count.

  2. Use a comma to separate three or more items—words, phrases, or clauses.

    Sunflowers grew on the hillsides, along the roads, and in the middle of every pasture.

  3. Use a comma to separate two or more adjectives that modify the same noun when they are not joined by a coordinating word. To decide if a comma is needed, reverse the two adjectives; if the sentence sounds wrong, a comma is not needed.

    Rescue workers found the frightened, hungry child.
    (The phrase hungry, frightened child sounds correct, so a comma is needed.)

    Local businesses donated the bright red uniforms.
    (The phrase red bright uniforms sounds wrong, so no comma is needed.)

  4. Use a comma to separate introductory words, phrases, and clauses from the rest of the sentence.

    When alcohol was outlawed, many citizens broke the law.

  5. Use a comma to set off a nonrestrictive word group from the rest of the sentence.

    Most people either love or hate fruitcake, which is a traditional holiday dessert.

    (The relative clause which is a traditional holiday dessert is nonrestrictive, so a comma is needed.)

  6. Use a comma to set off conjunctive adverbs.

    Islamic countries were, in fact, responsible for preserving much classical scientific knowledge.

  7. Use commas with dates, addresses, titles, and numbers.

    She graduated on June 12, 2001

    Send the package to General Delivery, McPherson, Kansas 67460.
    (A comma is not needed between the state and the ZIP code.)

    The featured speaker was Kate Silverstein, Ph.D.

    Estimates of the number of protesters ranged from 250,000 to 700,000.

  8. Use commas to separate direct quotations from the words that introduce or explain them.

    She asked, “What’s the score?”

    “Wait and see,” was his response.

  9. Use commas to set off the name of someone directly addressed, to set off an echo question, and with a "not" phrase.

    “Bail has not been granted, your honor.”

    More development will require a more expensive infrastructure, won’t it?

    Labor Day, not the autumnal equinox, marks the end of summer for most Americans.

Unnecessary commas

As you edit and proofread your papers, watch out for the following common errors in comma usage.

  1. Omit a comma between a subject and a verb.

    The poet Wilfred Owen, was killed a week before World War I ended.

  2. Omit a comma between a verb and a complement.

    The school referendum is considered, very likely to pass

  3. Omit a comma between an adjective and the word it modifies.

    A growing family needs a large, house.

  4. Omit a comma between two verbs in a compound predicate.

    We sat, and waited for our punishment.

  5. Omit a comma before the first or after the last item in a series.

    Anita had to meet with, Lou, Ian, and Stuart, for rehearsal.

  6. Omit a comma before a coordinating word joining two dependent clauses.

    The band began to play before we arrived, but after the rain stopped.

  7. Omit a comma when using indirect quotations.

    Aunt Dora said, that we could take the leftovers home.

  8. Omit a comma after like or such as.

    Direct marketing techniques such as, mass mailings and telephone solicitations can be effective.

  9. Omit commas around a restrictive word group that renames another word before it.

    The man, who brought his car in for transmission work, is a lawyer.