Punctuation: Comma

The comma ( , ) is one of the most commonly misused forms of punctuation. Omitting a comma causes information to run together, leading to a change in meaning or loss of clarity. Excessive commas cause information to become choppy and disconnected, confusing the reader. Avoid making these mistakes by learning the rules of comma usage.

Use commas to separate:

• Three or more items in a list: Homecoming is for students, alumni, parents, families and friends. (Do not include a comma before the conjunction in a simple series. This is known as an Oxford comma.)

• A series of adjectives equal in importance: WMU is a dynamic, learner-centered institution.

• Complete sentences that are combined with a conjunction: The event is open to the public free of charge, but reservations are required.

• An introductory phrase from the rest of a sentence: First, we must double the amount of external support.

• A nonessential phrase from the rest of a sentence: Sky Broncos, led by Steven Tkachuk, won the regional flight competition.

• Direct quotes: "We must support students in any way we can," the president said.

• Party affiliation, academic degrees and religious affiliations; and dates from years: Tim Greene, Ph.D., will compete in "Dancing with the WMU/Kazoo Stars" Oct. 30, 2009.

• Cities from names of states and nations; and names from hometowns and ages: Nate Knappen, of Grand Rapids, Mich., is the president of WSA.

• Yes and no; and names in a direct address: Yes, Mom, I'll be home for dinner.

• Similar words: What it really is, is justice.

https://wmich.edu/writing/punctuation/comma