A colon is used to introduce a list. It can be a formal introduction using as follows, or less formal.
The ceremony to honor Dr. Mills included everything: a moving introduction, a recitation of her achievements, a series of testimonials, and a glowing forecast of her future in the new position.
The questions were as follows: Where did you last work? For how long? What was your job title? What were your primary achievements?
Also, use a lowercase letter after the colon unless the list is a series of complete sentences, as in the second example. Use a capital letter after a colon in the situations described below.
Introducing a quotation or formal statement
The colon is used to introduce a quotation or formal statement. An independent clause must precede the colon. Capitalize the first word of a sentence following a colon only if the text that follows is a quotation or formal statement.
The speaker made the following observation: “In the future, communication between people all over the world will lead not to an enriched culture but to a homogenous one.”
Introducing a restatement or explanation
A colon may be used between two independent clauses when the second clause explains or restates the first clause.
The program was an unqualified success: hundreds of people attended.
These shoes are the best: they are durable, inexpensive, and stylish.
Notice that when the colon is used in this way (like a semicolon), it may be followed by a lowercase letter.
To test whether you should use a semicolon or a colon between clauses, ask yourself whether you could logically insert the phrase that is after the punctuation. If you can, use a colon; if you can't, use a semicolon.
These shoes are the best: that is, they are durable, inexpensive, and stylish. (correct)
A colon is appropriate in the previous example. The second clause explains the first clause. In the next sentence, the phrase that is doesn't work. Therefore, a semicolon is correct.
He struggled for years; that is, success finally arrived. (not logical)
He struggled for years; success finally arrived. (correct)
Colons with quotation marks
When using quotes in a sentence, always place colons outside quotation marks.
The article was called “ The Last Word” : his definitive statement.
This statement is from an article called “ Good Advice” : “Before you decide to marry a man, check out his relationship with his mother.”
A colon is used in the following special situations:
- To separate hours and minutes when writing the time
- To separate volume and number, or volume and page number of a magazine
Entertainment Weekly VI:4
National Geographic 87:53‐56
- To separate chapter and verse numbers for biblical passages
Jane Austen: A Feminist's View
- In the salutation of a business letter