In honor of National Punctuation Day, learn how to use colons.
AP Style: Sentence Fragments and Capitalization
Finally, let’s look at Associated Press style.
It’s like APA style in that you capitalize the first word after a colon if it’s the start of at least one complete sentence.
The huge difference is that AP colon rules allow you to use a colon after a sentence fragment. Whereas this sentence would be wrong in APA and Chicago style, it’s fine in AP style:
Aardvark’s moods are: grumpy and grumpier. (correct in AP style)
Similarly, if you have a sentence introducing a bulleted list, AP style allows you to put a colon after a sentence fragment like this:
Grammar Girl’s hobbies are:
Because I don’t like this style, I usually add the words “the following” before the colon. (“Grammar Girl’s hobbies are the following:”) It’s an easy way to make a fragment a complete sentence. But introductions to bulleted lists are also the place I see most people break the only-put-a-colon-after-a-complete-sentence rule, even if they follow it everywhere else. I know it looks wrong to a lot of people to have a line before a bulleted list without a colon at the end, so a lot of you probably like this style from AP. And that’s fine. You can like it.
To summarize, AP style lets you put a colon after a sentence fragment or a complete sentence, and you capitalize the first word after a colon if it’s the start of at least one complete sentence or is a proper noun.
Space After a Colon
Fortunately, there are at least a couple of colon rules on which all these three style guides agree:
First, put one space after a colon.
People often argue about how many spaces to put after a period (the short answer is that one space is more common these days), and the problem also comes up with colons. When people used typewriters, the style was to put two spaces after a colon; but now that almost everyone uses computers with word processing software, the common style is to put one space after a colon just as you would for a period.
Colons After Short Introductory Words
Second, colons are fine after short introductory words or phrases like “pros” and “cons” that are more like titles than sentences, and after names of people in a dialogue or transcript of a conversation. (AP and Chicago allow it. As far as I can tell, APA doesn’t address it, but I suspect it would be OK.)
Squiggly: Where is the chocolate I ordered for my truffles?
Aardvark: I think Fenster ate it.
Squiggly: Fenster has been out of town for a week.
Aardvark: Has he? Interesting.
Colons in Non-Sentence Usages
Colons are also used in some instances that aren’t sentences such as Bible verses, time, and citations:
5:43 (indicating volume 5, page 43 in Chicago style)
Create a Personal Style Sheet
As you can see from going over all these conflicting styles, there’s a good reason to decide which style you like best and write it down in a personal style sheet. If you read a lot, you’ll probably see colons handled differently every day, so it’s easy to get confused about which rules to follow, and being consistent in your own writing is one thing that makes it look more professional to readers.
Mignon Fogarty is Grammar Girl and the founder of Quick and Dirty Tips. Check out her New York Times best-seller, “Grammar Girl’s Quick and Dirty Tips for Better Writing.”