What Are Commas? (with Examples)

A comma (,) is a punctuation mark used to mark the divisions in text (as may be caused by phrases, clauses or conjunctions). Commas are used in lists to separate list items and in numbers to aid reading.

Below is a quick overview of when commas are used. Click here for a more comprehensive version of this list or click on the "Read more" link with each entry.

When to Use Commas (A Very Quick Overview)

Below is a quick overview on when to use commas.

(1) Use a comma after phrase or clause that "sets the scene" at the start of a sentence.
  • When I went to Paris, they just stared at me when I tried to speak French.
  • (The "introduction" is shaded.)
(2) Use a comma after a transitional phrase at the start of a sentence.

A transitional phrase is a term like However, Consequently, Therefore, and As a result.
  • Lee has eaten at least two pies a day for the last year. As a result, he has been placed in a high-risk group for diabetes.
  • (The transitional phrase is shaded.)
(3) Use a comma after an interjection.

An interjection is usually a short word inserted into a sentence to express an emotion or feeling.
  • Yes, my horse won.
  • (The interjection is shaded.)
(4) Use a comma before a conjunction that joins two independent clauses.

Words like and, or, and but are known as conjunctions.
  • Lee cannot sing, but he can dance
  • (Here, the conjunction but is joining two the independent clauses Lee cannot sing and he can dance.)
(5) Use commas as parentheses to offset a parenthesis.

Parentheses are punctuation marks (either commas, dashes or brackets) used in pairs to offset additional information in a sentence (known as a parenthesis).
  • The case has, in some respects, been not entirely devoid of interest.
(6) Use commas to separate list items.
  • Fish, chips, and peas
(7) Use a comma after a long subject if it aids your readers
  • Leaving a list of Internet passwords, increasing your life insurance and writing a will, will give you peace of mind while you are on operations.
  • (The long subject is shaded.)
(8) Use commas with numbers.

Commas can be used every 3 decimal places in large numbers to make them more readable.
  • 3,356
(9) Use commas before quotation marks when the quotation is introduced.
  • He said jokingly, "The world is my lobster."
(10) Use commas to offset words in the vocative case.
  • I know your sister, David.
  • (The word in the vocative case is shaded.)

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