These Are the Only Ways You Should Be Using a Colon

They may seem tricky, but they're easy to master.

You’ve probably seen these two little dots, one on top of the other, scattered throughout your reading material. But do you really know what they’re used for? The colon is not something that shows up in the majority of sentences, like a period, comma, or other punctuation marks. And its use is not outwardly obvious like an exclamation point or a question mark. So here’s a crash course in exactly when to use a colon. It’s good for a whole lot more than making the “eyes” of a smiley face emoticon, that’s for sure! Also, make sure you bookmark this piece on when to use a semicolon.

What is a colon?

A colon is an introductory punctuation mark. Its primary use is to present the information following the colon as something that builds upon the information before it. That sounds confusing, but it’s not as complicated as you think!

When to use a colon: Introducing a list or example

This is probably the best-known way to use a colon. You can use it to introduce a list or series, as in, “I’m excited for my classes this semester: Biology, History, English, and Algebra.” Here’s another example: “Please get these things when you go to the store: cheese, oranges, bread, and crackers.”

The items in the list can also be sentences on their own; they don’t have to be comprised in a single sentence. For instance, “Here are my conclusions: One, English grammar is complicated. Two, I want to get better at it. Three, I should read more grammar articles on Reader’s Digest.”

But the thing that you’re introducing with a colon doesn’t have to be a list. As you may have noticed, I used a colon in the first paragraph of this section, to introduce an example for when to use a colon! You can follow phrases like “Here’s an example” or “Try this” with a colon. Find out how confusing life would be without proper punctuation.

When to use a colon: Introduce a quote, subtitle, or subheading

Love franchise movies? You’ve probably encountered lots of colons in your moviegoing. Captain America: Civil War. Mad Max: Fury Road. Star Wars: Episode IV. The colon introduces a sort of “subtitle” to the movie. Books and even musical albums use this format as well: Bob Woodward’s Fear: Trump in the White House and BTS’s MAP OF THE SOUL : 7 are respective examples. (And, as you can see, I used a colon again to introduce those examples!) In addition, as you may have noticed, the subheadings of this piece use colons to introduce each individual use.

You can also use a colon to introduce a quotation. You could say, “Maya Angelou’s words always stick with me: ‘Try to be a rainbow in someone else’s cloud.'”

When to use a colon: Independent clauses

Here’s a slightly trickier way to use a colon. Technically, you can separate independent clauses with a colon as long as it makes sense (i.e., the first clause introduces the second). Think about the wisdom from Forrest Gump’s momma: “My momma always said life was like a box of chocolates: You never know what you’re gonna get.” Of course, the phrase in the film was spoken, not written, but you could use a colon here. You could also use a period and have the two clauses be separate sentences; they’d still be grammatically correct. But the use of a colon works too, because the second clause directly explains how life is like a box of chocolates (the first clause).

When to use a colon: Greetings

How do you start letters or emails? Do you start with “Dear [Recipient],” and then a comma? Well, it turns out that, in formal correspondences, that comma should be a colon. If you’re just chatting with a friend or replying to a more casual email from a colleague, a comma is fine. But if the correspondence is more formal, the greeting should be followed by a colon (even if it’s just “Dear”). “To Whom It May Concern” should always be followed by a colon.

When to use a colon: Numbers

And, last but not least, there are ways to use a colon that don’t involve introducing an idea. Colons are the punctuation marks that you’ll find in the representation of time (“11:45 pm”), Bible verses (“James 2:20”), and ratios (“1:2”).

How you’re using colons incorrectly

Now that you know these rules for when to use a colon, it’s important to know that you can’t just use them willy-nilly. You can’t simply stick a colon in the middle of a sentence, even if the sentence contains a list. To use the earlier example: “When you go to the store, please get: cheese, oranges, bread, and crackers” is incorrect. The content before the colon should be an independent clause.

In proper grammatical terms, this means that a colon should not “separate a noun from its verb, a verb from its object or subject complement, a preposition from its object, or a subject from its predicate,” Grammarly explains. But the bottom line is that if the sentence is grammatically correct without a colon, the colon should not be used. The incorrect example, “When you go to the store, please get: cheese, oranges, bread, and crackers,” is a grammatically correct sentence without the colon. Meanwhile, the correct example from earlier, “Please get these things when you go to the store: cheese, oranges, bread, and crackers,” is not a correct sentence without the colon. It is formatted in a way that requires the colon.

Here’s another example. “These are my dream vacations: Disney World, Machu Picchu, and the Amalfi Coast” is correct, while “Someday I want to visit: Disney World, Machu Picchu, and the Amalfi Coast” is incorrect.

Now that you know when to use a colon, learn about the most confusing grammar rules in the English language.

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Meghan Jones
Meghan Jones is a Staff Writer for RD.com who has been writing since before she could write. She graduated from Marist College with a Bachelor of Arts in English and has been writing for Reader's Digest since 2017. In spring 2017, her creative nonfiction piece "Anticipation" was published in Angles literary magazine. She is a proud Hufflepuff and member of Team Cap.