When to Use a Colon in Writing for Punctuation

A colon is used in punctuation for various reasons, from introducing a list or example to connecting clauses or following a salutation in formal correspondence. 

While they may not be used as frequently as some punctuation marks, colons are quite versatile and have a knack for creating a pause or introduction.

Learn best practices for when to use a colon for punctuation. Then, review your content with the Originality.ai AI Grammar Checker to catch spelling, grammar, and punctuation mistakes. 

What Is a Colon in Punctuation?

You can recognize a colon in punctuation by looking for two periods (.) that look like they are stacked on each other (:). 

You don’t use a colon as an end punctuation mark when writing a sentence. Its main job is introducing something within a sentence, but a comma’s usefulness doesn’t end there.

Let’s look at some key scenarios where a colon is used in punctuation:

A Colon May Appear at the Beginning of a List

In writing, you can use a colon to begin writing a list of items. The colon and the list must follow an independent clause (a clause with a subject and predicate that can stand on its own). 

Examples of a colon beginning a list: 

• She told me to buy three things: eggs, milk, and butter.
• I invited my whole friend group: Sam, Max, Brenda, and Tammy.
• I am taking three classes: gym, English, and cooking. 

Notice that the clause preceding the colon in the examples above could be a complete sentence on its own (an independent clause). 

If the clause preceding the colon is a dependent clause, the colon is unnecessary. Instead, just go directly into the list.

Colons that appear next to a dependent clause aren’t necessary: 

• Incorrect:  She told me to buy: eggs, milk, and butter. 
  
  • Correction: She told me to buy eggs, milk, and butter. 
• Incorrect:  I am taking: gym, English, and cooking.
  
  • Correction: I am taking gym, English, and cooking. 

Colons Can Introduce a Bulleted or Numbered List

In marketing, academic, or technical writing, sometimes a list will appear in bullet points or a numbered list, preceded by some introductory copy. A colon is used to separate the list from the sentence.

Examples of a colon introducing a bullet point or numbered list:

Example 1: 

Attend our seminar for its many benefits:

• Renowned keynote.
• Great interactive sessions.
• Free lunch.

Example 2:

Registration is easy:

1. Go to our website.
2. Fill in your details.
3. Complete payment.

A Colon May Introduce a Quotation

A colon can be used to introduce a quotation or dialogue when a writer wants to place additional emphasis on the quote or formally introduce it. Generally, this is a stylistic choice. 

Example of a colon introducing quotations:

• She was ready to deliver the report: “It’s good news,” she said.

In this case, the colon isn’t necessary. It could just as easily be replaced with a period, breaking the line into two sentences:

• She was ready to deliver the report. “It’s good news,” she said.

However, the colon adds a bit more drama or anticipation by connecting the parts and creating a slight dramatic pause. In contrast, the period creates a hard stop which might make the quotation feel flat in creative writing.

Example of a colon introducing dialogue:

• In Shakespeare’s Hamlet, Hamlet states: “To be, or not to be, that is the question.”

Again, this is a stylistic choice. A comma could replace that colon and be grammatically correct. 

• In Shakespeare’s Hamlet, Hamlet states, “To be, or not to be, that is the question.”

So, in this case, the colon serves as a pause and adds emphasis to what is stated. 

Colons are Often Used in Scripts or Interviews

Colons are used in dialogue, screenplays, or interviews to separate the question and answer or speaker and spoken words.

Examples of colons in scripts or interviews:

Example 1:

Harry: Where are you going?

Sally: None of your business.

Example 2: 

Q: When did you get started in acting?

A: I moved to Hollywood when I was 16. 

You Can Place a Colon Between Two Independent Clauses

It is usually the job of a semicolon to join two independent clauses. However, when the second clause illustrates or modifies the first clause, joining them with a colon emphasizes their relationship to one another. 

Examples of a colon joining two independent clauses:

• You are right: this cake is delicious.
• He got a ticket: he was over the speed limit. 
• The car is fast and cheap: that’s why I bought it. 

In most cases, you do not capitalize the word after the colon unless it is a proper noun or a quotation:

• I love reading plays: Shakespeare is my favorite.
• You know what I always say: “Live and let live.”

Colons Separate Titles and Subtitles

In writing you can use a colon to separate a title and subtitle. Subtitles, by definition, explain, clarify or provide further context to a title. So, it is fitting that a colon appears between a title and its subtitle as both a separator, a connector, and something that provides emphasis or clarity.

Examples of colons separating a title and subtitle:

• “Thor: The Dark World”
• “Pirates of the Caribbean: Dead Men Tell No Tales”

Colons in Formal Correspondence

When addressing someone in a business email or letter, using a colon after the greeting or salutation signals formality.

Examples of colons in formal correspondence: 

• Dear Sir:
• Dear Mrs. Smith:
• To the hiring committee:

Colons Used With Numbers

Colons have some special uses when it comes to numbers:

• Between the hour and minutes in time: 12:00 A.M., 2:30 P.M.
• Between the two numbers in a ratio: 1:3

Colons With Other Punctuation

Colons don’t often appear next to most forms of punctuation, but when they do appear, there are some rules:

• Colons always go outside closing quotation marks
  
  • The recipe is supposedly “easy”: it has 20 steps.
• Colons always come after a closing parenthesis.
  
  • The recipe is supposedly easy (yeah, right): it has 20 steps.

Final Thoughts

Using colons can add to writing. When used correctly — and sparingly — a colon for emphasis or dramatic pause can add to the rhythm of your writing. 

Review your writing with the Originality.ai AI Grammar Checker to see if you’ve incorporated colons and other punctuation correctly. Plus, check for spelling and grammar errors so you can publish with confidence.

Learn more about punctuation and grammar in our resources:

• When to Use Question Marks: A Complete Guide
• A Guide to Using Exclamation Marks in Writing
• How to Use an Apostrophe + Examples