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What Are Colons (:) And How Do You Use Them?

When writing using proper grammar, it is important to remember proper punctuation. Punctuation is the system of symbols and marks we use in writing, such as the period, question mark, and comma. Right now, we are going to look at one specific punctuation mark: the colon. While it may not be as commonly used as the period or the comma, the colon is useful for connecting sentences and placing emphasis on a word or phrase. Like all other punctuation marks, though, the colon involves something that causes many people problems: the rules of grammar.


What is a colon?

A colon is a punctuation mark that is used to divide a sentence. The colon resembles two dots positioned vertically (:). The colon has a variety of uses, some of which include introducing a list, introducing an explanation, introducing a quote, and connecting two related sentences.

✏️Examples of a colon in a sentence

The following sentences show just some of the ways we can use a colon in a sentence. 

  • Sasha owns three dogs: a beagle, a Dalmatian, and a husky.
  • Benjamin Franklin said my favorite quote: “There was never a good war or a bad peace.”
  • I stopped to consider an important question: Did I turn the faucet off?
  • The priest read the text of Exodus 4:10.
  • The odds were 2:1.

When do you use a colon?

The colon has a lot of different uses. We will briefly look at a few of them.

Introducing additional information

A particularly common reason to use a colon is to introduce information that is related to the sentence that preceded it. Often, the colon is used to set a word or phrase apart in order to give it emphasis or draw attention to it. This special information could include:

  • A list: I need several things from the store: eggs, milk, and bread. 
  • A noun or noun phrase: The weapon to defeat the beast was something nobody expected: love.
  • A quote: My dad told me something I will never forget: “Pineapple on pizza is an abomination.”

Connecting two related sentences

A colon can be used to connect two independent sentences. Typically, a colon is used when the second sentence clarifies or explains the first sentence. For example,

  • Me and my sisters are really excited: We’re going to Disneyland!

In the example above, we can see that the second sentence is closely related to the one that came before it. If we had used a period instead, the sentences would seem more distant and we would lose the relationship.

This particular usage is similar to how another punctuation mark, the semicolon, is used. In general, the semicolon is also used to connect related sentences. However, there is a slight difference in how these two punctuation marks are typically used. In general, the two sentences connected by a semicolon are less specifically related to each other than those connected by a colon. The sentence following a semicolon may not describe or explain the previous sentence.

Here is an example showing the difference how colon and semicolons are generally used:

  • Colon: Jeremy raised a very important question: who had invited us all to the spooky house? (The second sentence clarifies the first sentence by revealing what Jeremy’s question was.)
  • Semicolon: Jeremy raised a very important question; it was a question nobody thought to ask. (These two sentences are related, but the second sentence doesn’t explain or clarify the first.)

Learn all the ins and outs of using a semicolon correctly, here.

Other uses

There are a few other instances where you might see a colon used. These uses are based more on formatting or style guides rather than grammar. Some non-grammatical uses of colons include:

  • Time: We need to be at the hotel by 5:45 p.m.
  • Biblical passage: She quoted Ezekiel 6:5 in her speech.
  • Ratio: The odds of my horse winning are 10:1.

How to use a colon

There are few things to be careful of when using a colon.

Colons typically follow a complete sentence

Regardless of what follows a colon, most grammar resources agree that only a complete sentence should come before it. For example,

❌ Incorrect: I have a lot of stuff in my closet, including: hats, toys, and even a guitar.
Correct: I have a lot of stuff in my closet: hats, toys, and even a guitar.

❌ Incorrect: Stuff I need: nails, screws, and wood.
✅ Correct: Here is the stuff I need: nails, screws, and wood.

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Capitalization

The rules of capitalization following a colon depend on which style guide or grammar resource you use. Most style guides (such as the American Psychological Association’s) recommend a general rule: If a complete sentence follows a colon, use a capital letter. (While we’ve just demonstrated how to do this correctly, please note Dictionary.com and Thesaurus.com lowercase after a colon in almost all instances per our own style guidelines.)

If a single word or a sentence fragment follows a colon, it is usually recommended to use a lowercase letter unless a colon is immediately followed by a proper noun. For example,

  • I am afraid of almost anything: mice, bugs, heights, you name it. (sentence fragment)
  • Through all of our adventures, we learned one important thing: Never take advice from mischievous imps! (complete sentence)
  • We have been to many countries: France, Spain, Russia, Japan, and Brazil, just to name a few. (proper noun)

Quiz yourself on the difference between colons and semicolons.

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Confused about parentheses? We've put aside this helpful explainer for you.

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