Colons can be tricky little suckers. Knowing when to use a colon—and how to use it properly—is difficult. Even the most well-known and respected style manuals, the Chicago Manual of Style and the AP Style Handbook, disagree!
On top of that, knowing when to use a colon often depends on your stylistic choice. Yes, you read that correctly. It’s your choice! Now before you run away from reading the rest of this article, you first need to know the rules about colons, in order to make an appropriate choice about when to use a colon.
Two Basic Formats for When To Use a Colon
Fundamentally, there are two formats when you will use a colon in your writing. These formats are:
- Within a sentence
- Before or within a vertical list, such as:
- Bulleted lists
- Numeric lists
- Lists without an order, bullets, or numbers
There are numerous other situations where colons are used—like in citations, indexes, and time references—but those are specific issues to be discussed another day. For now we will stick to when to use a colon in the body of your writing.
When to Use A Colon Within a Sentence or Paragraph
Generally, you can think of a colon as a punctuation mark that anticipates something additional coming. It’s a mark that says, “Here’s what I mean.”
Rules to Remember
- The hard and fast rule is that a colon must ALWAYS follow a complete sentence. Do not use a colon after a sentence fragment, ever.
- A colon is used after a full sentence or independent clause to introduce something that illustrates, clarifies, or amplifies what was said in the sentence that preceded the colon.
- You can also use the following formula to remember when to use a colon.
Full sentence + colon + list, fragment, or full sentence that clarifies or amplifies the first full sentence.
- Wendy only likes two flavors of ice cream: vanilla and chocolate.
Wendy only likes two flavors of ice cream is a full sentence on its own.
Vanilla and chocolate is the fragment that clarifies which two flavors she likes.
Now note that a colon does not have to be used here. You could use a simple comma instead. Here is an example of when it is a stylistic choice whether to use a colon or not. A colon breaks up the sentence a bit more, and amplifies “vanilla” and “chocolate” by visually setting it apart from the rest of the sentence. Colons also tend to make your writing look a bit more formal than the relaxed and much more frequently used comma.
- Wendy’s favorite flavors of ice cream are: vanilla and chocolate.
This is a slight variation on Example #1. But, this is wrong!
Why? Because in this example, the text that comes before the colon is not a complete sentence. This is usually true whenever the last word before the colon is a verb. Here, obviously, the verb is “are.” This violates the first rule: Never use a colon after anything but a full sentence.
To correct this, you could add the fragment “the following” or “as follows” right before the colon.
- Wendy’s favorite flavors of ice cream are the following: vanilla and chocolate.
Personally, I think that makes the sentence longer than necessary. With good writing these days, it is important to get to the point as quickly as possible.
- Sentence 1: I want the following: butter, cinnamon, and chocolate.
Sentence 2: I want butter, cinnamon, and chocolate.
Today, good writing means using as few words as possible to make your point. Long, convoluted sentences should be avoided.
Now, even though this is a very simple example, writers often use colons in a way that may be grammatically correct, but not preferred. (Also, many people assume that a colon is always needed before a list. Not necessarily so!) In this example, the second sentence is simple and to the point.
A Note on Capitalization After Colons
Let’s talk about capitalization after colons. Did you see what I did in Example #2 above? I capitalized the “N” in “Never.”
- This violates the first rule: Never use a colon after anything but a sentence.
This is also tricky. Generally speaking, the word following a colon should not be capitalized in a sentence. (Bulleted lists are different.)
Now, the exception—darn those pesky exceptions—is when you are using a colon to connect two independent clauses (full sentences). Here, the authorities are split. Some say to use a capital letter when connecting two sentences. Some say don’t use a capital letters. Still others say it’s a stylistic choice!
But they do agree on a few things.
Rules to Remember
- If the sentence after the colon is closely related to the first sentence: don’t use a capital letter to begin your second sentence. (Let this sentence be your example here!)
- Use a capital letter if the first sentence introduces a quotation.
After the ceremony, the pastor made an announcement: “The reception will follow in the fellowship hall in 30 minutes.”
You would do well to remember the old saying: The early bird catches the worm.
- Use a capital letter if you are using the colon to introduce a series of related sentences.
Susan faced a decision: She could RSVP to the reunion organizer saying that she would be there, and then just not show up. She could RSVP with a fictitious excuse and stay home. Or she could suck it up, and go to the reunion despite her reluctance to face all her former classmates.
When to Use A Colon in Bulleted Lists
Writing must be reader-friendly. That means no long, protracted expositions as in the days of Clarence Darrow and Charles Dickens.
People today—especially people searching for information online—want the facts quickly! They don’t want to read through 10 pages of material to find what they are looking for. Bulleted lists help a writer get their point across succinctly, and help the reader to skim and find what they’re looking for.
So how do colons function in bulleted lists?
Rules to Remember
- Colons can introduce a bulleted list, using a full sentence followed by a colon.
- If each item in a bulleted or numbered list is a full sentence, start the sentence with a capital letter. Use the proper ending punctuation, which is usually a period.
- Other than that, the rest is really a stylistic choice. Here again, grammarians don’t agree, so it’s largely up to you.
I need an assistant that is able to do the following:
- Type 70 WPM
- Edit court motions
- Do legal research
If the items in your list are single words or short fragments, it is advisable to put no punctuation at the end of each element.
Whether or not you capitalize is up to you. Capitals are optional in this example. However, in my opinion, a capital first letter emphasizes the point a bit better.
Here are the rules of the park play area:
- No pushing or shoving is allowed.
- You must wait your turn if others are ahead of you.
- Report bad behavior to the adult who is with you.
- Be polite and wear a smile!
- Have fun!
If the list is comprised of full sentences, it is best to punctuate and capitalize as full sentences.
A Final Word on When to Use a Colon
Colons can be overused easily. Some people think colons and semicolons make their work seem more professional. But overuse of these punctuation marks can actually make your writing harder to read.
When to use a colon can be tricky. When you’re about to use one, be sure to refer to manuals, blogs, reference guides, and our lessons until it becomes second nature!