Learn how and when to use a colon (:) with examples and useful colon punctuation rules. The mark (:) in the middle of a sentence indicates that the second half of the sentence explains or provides examples of what is described in the first half.
What is a colon?
The punctuation mark (:) consists of two dots, one above the other. It signals that the second half of the sentence is going to explain or give examples of something mentioned in the first half.
- I’m taking four classes this semester: biology, philosophy, physics, and ancient Greek.
- I’ll give him credit for one thing: he’s certainly persistent.
When to use a colon
Use the mark to introduce something in the second half of the sentence that explains, completes, or gives examples of what is mentioned in the first half.
It may introduce a list.
- The following novels will be on the exam: Moby Dick, Great Expectations, and The Brothers Karamazov.
- Here are some of my favorite foods: fried chicken, lobster, and corn on the cob.
The mark (:) may introduce an explanation or example.
- She’s ready to move on to a new school: this one has taught her everything that’s available there.
- Amsterdam is filled with great museums: just walk around and you’ll find one.
Unlike the semicolon, the colon may introduce a clause or just a series of nouns that do not form a complete sentence.
- Complete sentence: Manchester United face a difficult task: they must win the next six matches.
- Clause: Bring me a 50-lb. box of cat litter: the kind that contains deodorant.
- List: We’re ready for the following patients: López, Santamaria, Trinidad, Rincónes.
The mark (:) may also be used to build up to something that is revealed after the colon.
- I can bring a great strength to your company: my writing skills.
- She said she wanted to be sure to go to one place before she died: New Zealand.
How to use the colon with quotation marks
The mark (:) always goes outside the closing quotation mark, whether you are writing British or American English.
- “Always look before you leap”: that is useful advice.
If both halves of the sentence are complete sentences in themselves, either a colon or a semicolon may often be used. The mark (:) places greater emphasis on what comes after the colon.
- We can enter at the next gate; there are fewer people there.
- We have a problem: hundreds of people are outside, but we have nothing to sell to them.