In honor of National Punctuation Day, learn how to use colons.

Mignon Fogarty

Today's topic is how to use colons.

One of my favorite old grammar books, titled "Punctuate It Right," has a wonderful name for the colon: the author calls it the mark of expectation or addition. That's because the colon signals that what comes next is directly related to the previous sentence. Often, it’s almost a definition of what came before.

Use Colons After Complete Sentences

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Style guides differ significantly, however, when it comes to colons, so the most important thing is to know what style guide you should be following and what rules it recommends. The two main rules that differ are whether you can use a colon after a sentence fragment and whether you capitalize the first word after a colon.

If you don’t follow a specific style guide, you can pick the rules that you like best. Just be sure to use them consistently. Making your own personal style sheet is one way to make it easier to be consistent in the future. If you like a style, write it down.

APA Style: Complete Sentences and Capitalization

I’ll start with the style I like best, which is APA style: the style of the American Psychological Association. 

1) In APA style, you use a colon only after a complete introductory clause. In other words, after only something that could stand on its own as a complete sentence. 

Squiggly has one dream: becoming a chocolatier. (correct in APA style)

Squiggly bought: chocolate chips, butter, and a spatula. (incorrect in APA style)

2) In APA style, you capitalize the first word after a colon if it’s the start of at least one complete sentence (or of course, if it’s a proper noun).

Squiggly has one dream: He dreams of becoming a chocolatier. (correct in APA style)

Squiggly has one dream: he dreams of becoming a chocolatier. (incorrect in APA style)

So in APA style, you can use a colon only after a complete sentence, and you capitalize the first word after a colon when it’s the start of a complete sentence. 


About the Author

Mignon Fogarty

Mignon Fogarty is the founder of the Quick and Dirty Tips network and creator of Grammar Girl, which has been named one of Writer's Digest's 101 best websites for writers multiple times. The Grammar Girl podcast has also won Best Education Podcast multiple times in the Podcast Awards, and Mignon is an inductee in the Podcasting Hall of Fame. Mignon is the author of the New York Times best-seller "Grammar Girl's Quick and Dirty Tips for Better Writing" and six other books on writing. She has appeared as a guest on the "Oprah Winfrey Show" and the "Today Show" and has been featured in the New York Times, Business Week, the Washington Post, USA Today, CNN.com, and more. She was previously the chair of media entrepreneurship in the Reynolds School of Journalism in Reno, NV. She hates the phrase "grammar nazi" and loves the word "kerfuffle." She has a B.A. in English from the University of Washington in Seattle and an M.S. in biology from Stanford University. Mignon believes that learning is fun, and the vast rules of grammar are wonderful fodder for lifelong study. 

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