Colons

How to Use a Colon

The colon is one of the most misused punctuation marks in writing. So how is it used in writing? In formatting?

Before Lists

Use a colon after an independent clause (a full sentence containing a subject, verb, and a complete thought) and before a list:

I bought several items at the store: oat milk, discount sunglasses, and mints.
I am taking three classes this semester: English 1021, Psychology 101, and History 225.

In the following sentences, there is not a full sentence, so no colon would be used:

I bought several items at the store such as: oat milk, discount sunglasses, and mints.
I am taking three classes this semester, which are: English 1021, Psychology 101, and History 225.

Read the sentence before the colon again. Does it make sense to end a sentence with “such as” or “which are”? Probably not- it would create a fragment. Therefore, no colon is needed to separate the list from the sentence. To fix these, we'd just remove the colon.

Before a Quotation

Use a colon before a quote, but again, make sure there's a full sentence beforehand.

The writing tutor gave me some great advice on my essay: “Make sure everything in the essay relates to the thesis statement.”
My poetry instructor regularly used her favorite quote from Robert Frost: “Nothing gold can stay.”

For Emphasis

Use a colon between two sentences when the second clause emphasizes or explains the first.

My grandfather gave me some great advice: he told me to get a good education and always work hard.
I always recommend the local Italian restaurant to visitors: it offers an extensive menu and the prices are reasonable.