Punctuation: How to Use a Colon (:)

A colon is used in two ways:

1) to introduce a list

  • Please bring these items: a towel, a swimming suit, and a hat.

2) to connect a sentence with another sentence/clause/noun that explains the meaning of the first sentence.

  • John realized why he loved his job: It made him a better person. (colon introducing a clause)

Here the second sentence explains the reason presented in the first sentence.

  • Lisa only had one option left: divorce. (colon introducing a noun)

Again, here, the noun in after the colon (“divorce”) explains the option introduced in the first sentence.

Below are the main rules for using a colon.

sunglasses and a towel at the beach

Please bring the following: a towel and sunglasses.

Rule 1: Use a Colon after an Independent Clause

An independent clause is a complete thought or complete sentence. Let’s look at the same examples:

  • Please bring these items: a towel, a swimming suit, and a hat.
  • Lisa only had one option left: divorce.
  • His father gave John several responsibilities: feeding the dog, taking out the garbage, and washing the dishes.

Here, the underlined independent clauses are complete thoughts because they make sense by themselves because they have a subject verb, and object (except in the second sentence where no object is needed). A colon should only be used after an independent clause. Another way to think about is that if you cannot put a period (.) after the clause (periods only go after complete sentences), then you should not put a colon.

Common Mistakes with Colons

Using a Colon after a Verb or Preposition Unnecessarily

Do not put a colon if the sentence doesn’t need it. These sentences are mistakes:

I want to: eat, shower, and sleep.  (Incorrect)

I want to is not an independent clause; it is an incomplete thought. You cannot put a colon here. Also, you don’t need a colon to put a list after the verb want.

I want to eat, shower, and sleep. (Correct without a colon)

Here’s another example:

She ordered: a pizza, chicken wings, and a drink. (Incorrect)

Again, there’s no need for a colon here. We do not put colons after a verb if the sentence is not complete. The verb order here is being used in a transitive sense (it is followed by an object). Do not break up a verb and its object with a colon.

She ordered a pizza, chicken wings, and a drink. (Correct)

Common Colon Collocations (Words often used to Introduce a List)

Here…:

  • Here’s the shopping list: apples, bananas, and sugar.
  • Here’s what you should do: open the box, put it on a plate, and then eat it.
  • Here are the answers: 1, 2, and 3.

…. the following: (useful for business/professional emails)

  • Please do the following:
    1. Download the file.
    2. Open it.
    3. Read its contents.

…. as follows: (useful for business/professional emails)

  • Please do as follows:
    1. Download the file
    2. Open it
    3. Read its contents

Capitalization with Colons

There is some debate about capitalization after a colon. You should not capitalize a list of words after a colon that do not form an independent clause. Nonetheless, if you have an independent clause after a colon, you can choose to capitalize the first letter.

  • I don’t like most fruit: bananas, apples, and oranges. (no capitalization)
  • My father reminded me of an important thing: He loves me. (capitalization is possible here because He loves me is a full sentence/independent clause)
  • There was still one issue the police didn’t understand: How did the thief get into the building? (How is capitalized because of the independent clause (a question) after the colon).

Sidenote: How do I use a Semi-colon? (;)

A semi-colon is used differently. In short, a semi-colon is used to join two independent clauses that . In this sense, it is similar to a conjunction. See our full lesson here.

Found a mistake? Have a question? Leave a comment below.

– Created by Matthew Barton of Englishcurrent.com (copyright)

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