Punctuating With the Colon: Do’s and Don’ts

www.RuthlessEditor.comThe two little dots that make up the colon seem pretty simple, but their grammatical use isn’t exactly straightforward.

The colon comes in handy when you want to provide an example or explanation, to cite a quotation, or to introduce a list. A colon implies that what follows it is related to what precedes it.

One of the most-asked questions I get about grammar rules that relate to the colon is whether to capitalize the first word that follows it. Style guides differ, but The Associated Press Stylebook, my preferred source, suggests:

Capitalize the first word after the colon if what follows it constitutes a complete sentence (has a subject and verb):

If you want to grow daisies, remember this: For daisies to thrive, they should be planted in full sun.
Council members agreed on one point: There will not be a crosswalk at that intersection.
He told me the same thing: The class will be offered at the start of the fall semester.

Do not capitalize the first word if the colon is followed by a list or by phrasing that does not form a complete sentence:

My parents had a hard-and-fast rule: no television until homework was done.
I need these ingredients for spinach salad: fresh spinach, balsamic vinegar, olive oil, honey, strawberries.
There are many reasons college freshmen gain weight their first year away from home: stress, dorm food, late-night study snacks, and of course beer.

If you introduce a list with including, namely or for instance, do not use a colon:

I made a trip to the store to pick up the ingredients I need for spinach salad, including fresh spinach, balsamic vinegar, olive oil, honey and strawberries.
There are many reasons college freshmen gain weight their first year away from home — namely stress, dorm food, late-night study snacks, and of course beer.
Some travel recommendations are, for instance, booking early flights, having just a carry-on, and getting to the airport at least 90 minutes before departure.

A colon goes outside of quotation marks when it is not part of the quoted element:

The trainer emphasized three elements of what she called “high-touch service”: listening, eye contact and a firm handshake.
The following may enter the door marked “Backstage”: vocalists, keyboardists, percussionists, and guitar and bass players.

An American Psychological Association blogger agrees with AP; he says to capitalize the first word after a colon if it begins a complete sentence.

But not every source suggests capitalizing the first word of a complete sentence that follows a colon.

The Chicago Manual of Style differs from AP and APA:

When a colon is used to introduce a list or a single sentence, use lowercase for the first word after the colon. But capitalize the word after a colon when it introduces two or more related complete sentences.

However, in a FAQ section, CMS deems it “fine” to capitalize the first word that introduces one complete sentence.

Suggestions for colon use provide a perfect example of why grammar rules are confusing. My advice: Choose your preference and be consistent.

Do you have a punctuation question? Let me know! It might make a good blog topic.

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Kathy Watson

Kathy Watson has a love/hate relationship with grammar; she loves words and the punctuation that helps them make sense, yet she hates those pesky rules. A self-proclaimed ruthless editor, she prefers standard usage guidelines of The Associated Press Stylebook. Her easy-to-use Grammar for People Who Hate Rules helps people write and speak with authority and confidence. She encourages and welcomes questions and comments. (Email)

2 thoughts on “Punctuating With the Colon: Do’s and Don’ts

  1. AvatarPat (Heffernan) Kothe

    Hi Kathy,

    Please explain when to use “may” and when to use “might.”
    Should the period in the previous sentence been outside the quotation marks, and how do I
    determine when to do so?


    1. Kathy WatsonKathy Watson Post author

      Pat, I’d love to tackle “may” versus “might.”
      And, yes, periods (and commas) ALWAYS go inside quotation marks in American English.
      If you have these kinds of questions, others probably do as well. I’ll be happy to do a blog on each.

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