5 Rules of Colon Usage

Colons (:) can be confusing, that's true, but their function is actually quite straightforward: they introduce related information. Learn how to use a colon correctly to give your writing more clarity.

colon rules usage example colon rules usage example

What Is a Colon?

Curious about colons? You’ve come to the right place. A colon is written as two dots on top of each other (:), and it is used to separate independent clauses among other things. A space or return is placed directly after a colon.

Using colons in a sentence can be tricky. Without knowing how to use colons, a writer can end up just putting colons everywhere, nowhere at all or interchanging the colon with a semicolon or comma. To avoid precisely that, let's take a look at these 5 rules of colon usage.

Rule 1: Use a Colon to Introduce an Item or List

Use a colon to introduce an item or list, if the list comes after a complete sentence or independent clause. For example:

  • There are three things every dog needs: food, water and healthcare.
  • You need to grab these three things for the laundry: laundry detergent, fabric softener and dryer sheets.
  • For the camping trip, you need to pack many things: clothing, sleeping bags, food, utensils, and cookware.

The first word of the item is only capitalized if it is a proper noun.

  • This year I want to visit four amazing cities: Paris, London, New York, and Barcelona.
  • When you go to Michigan, you want to make sure to visit all the important cities: Lansing, Sault Ste. Marie and Detroit.

However, you won’t include the colon after a verb or preposition where it separates them from the objects.

  • Incorrect: We need: eggs, milk and fabric softener.
  • Correct: We need eggs, milk and fabric softener.

Rule 2: Use Colons Between Two Sentences

Use colons between two sentences if the second sentence emphasizes or illustrates the first. View some examples of this in action.

  • Thinking back, our trip to Ireland was the best: we saw some of the most beautiful terrains this Earth has to offer.
  • Diane deserved this degree: she got what she worked for.
  • Life is like a road: every path takes you somewhere.
  • The results are in: he is the president.

When using a colon in this manner, the beginning of the second sentence is in lower case.

Rule 3: Use a Colon to Introduce a Bulleted or Numbered List

Use a colon to introduce a bulleted or numbered list. The colon comes right before the bulleted list as you can see in this example.

The English language is spectacular. There are 14 different types of punctuation marks:

- periods
- question marks
- exclamation points
- commas
- semicolons
- colons
- dashes
- hyphens
- brackets
- braces
- parentheses
- apostrophes
- quotation marks
- ellipses

Capitalization and ending punctuation are optional for single words or short phrases in bullet points or numbered lists.


Rule 4: Use a Colon to Introduce Extended Quotations

Use a colon to introduce extended quotations. You should not use quotation marks and you should single space the quotation and indent from the left margin. Check out how a colon works for an extended quotation.

Dyer's philosophy can be summed up in his belief that our thoughts manifest our reality:

Act as if what you intend to manifest in life is already a reality. Eliminate thoughts of conditions, limitations, or the possibility of it not manifesting. If left undisturbed in your mind and in the mind of intention simultaneously, it will germinate in the physical world.

Use a colon to separate a full sentence quote. You include a capital letter to start the quotation.

  • Diane announced to the group: “Dinner is ready everyone.”
  • The group shouted to the clouds: “We graduated high school.”

Rule 5: Use a Colon Following a Greeting

Use a colon following a greeting (also known as a salutation) in a formal or business letter. It does not matter if you are using the person's first name, both first and last name, or their title, you should always use a colon if the letter is formal. If the letter is personal, then either a colon or comma is appropriate.

  • To Whom It May Concern:
  • Dear Mr. Wilson:
  • Dear Professor Jason Smith:

How To Use a Colon Correctly

See, we told you the grammar rules for using a colon are pretty straightforward. Just remember that a colon isn't a comma, nor is it interchangeable for one. To solidify this in your mind, take a look at 8 times commas were important. It'll help bring it all home for you.