Expert Commentary

Chicago Manual of Style basics

If The Associated Press Stylebook was created specifically for journalists, the target audience of The Chicago Manual of Style is much broader — all writing and writers.

If The Associated Press Stylebook was created specifically for journalists, the target audience of The Chicago Manual of Style is much broader — all writing and writers. While one can debate the merits of Chicago versus AP style, Chicago’s strength is its breadth and depth.

A simple measure is to look at page counts: The most recent edition of AP is 420 pages, while Chicago has more than twice as many pages with much more dense type. The end result of all those additional pages and content is more guidelines, examples and authority. And unlike AP, Chicago style reflects the current state of the art in typography — accents and italics are embraced, for example.

Chicago style clashes with journalism writing on two points. First, the guide is so inclusive that finding what you’re looking for can occasionally be difficult. Second, Chicago’s sweet spot is long-form writing, and this is reflected in some of its stylistic decision: the numbers below 100 are spelled out, for example, not a rule one wants to have to observe in a 20-word blog post.

The solution is a journalism-specific interpretation of Chicago that uses some of AP’s general principals without being their prisoner. Below you’ll find information on numbers, time and dates, locations, phone numbers, punctuation, capitalization and titles, lists, and the Internet. This isn’t an exhaustive list, but it will get you started.


One through nine are spelled out, 10 and above are figures (Arabic numerals). If a sentence begins with a number — even a year — it should be spelled out or the sentence rewritten. Use figures in tables.

Percentages: Always use figures and when possible, the word percent. In space-constrained contexts such as tables, the % symbol can be used.

Million, billion: Always use figures and spell out the words million andbillion.

Time and date

Month, day: Spell out the month and use figures for the day: “The symposium took place April 2.” Avoid the use of figures for the month, as in “1/2/2011,” which could be read as either January 2 or February 1.

Month, year: If month, day, and year are present, set off the year with matching commas. Otherwise, don’t use commas. “The morning of June 12, 1964, the sun rose early”; “February 2009 was particularly cold.”

Decades: Do not use an apostrophe between the year and final s: “Macrame was popular in the 1970s.” If you omit the first part of the year, use an apostrophe to indicate the missing digits: “Goth music got its start in the ’80s.” If you spell out the decade, capitalize it: “The Sixties were a time of change.”

Time: Use lowercase a.m. and p.m., with periods. Always use figures, with a space between the time and the a.m. or p.m. If it’s an exact hour, no “:00” is required. “By 6:30 a.m. she was long gone.” If a time range is entirely in the morning or evening, use a.m. or p.m. only once: “6:30–10 p.m.” If it goes from the morning into the evening (or vice versa), you need both: “10 a.m.–2 p.m.”

Cities, states

When used on their own, state names should be spelled out: “Massachusetts is on the Atlantic Ocean.” When there’s a city, abbreviate: “Cambridge, Mass., is a hip place.” The two-letter forms of state names are used only with zip codes: “Send mail to 79 JFK St., Cambridge, MA 02138.”

Phone numbers

U.S. area codes get no special treatment and aren’t preceded by a 1. Use hyphens between groups of numbers: “Call 617-495-8269 to reach the Shorenstein Center.” With international numbers, put the country code first, preceded by a plus sign. Separate number groups with spaces and indicate optional digits with parentheses: “The main number in Paris is +33 (0)1 44 41 88 88.”


Hyphen: Hyphenate compound adjectives only if required for clarity: “fastest-growing company”; “high-level discussion.” Don’t use hyphens with commonly understood terms, adverbs that end in ly, and between figures and units of measure: “greatly exaggerated claims”; “2 percent rule.”

Em-dash: Em-dashes are the widest commonly used dash and can either indicate a break in thought or set off part of a sentence: “Felipe’s is a popular eatery — in Harvard Square, anyway.” If at all possible, use a real em-dash character surrounded by spaces. When using text editors that don’t support em-dashes, use two hyphens for each dash.

En-dash: An en-dash is wider than a hyphen but narrower than an em-dash. It shows continuity between numbers and indicates that a multiword term is part of a compound adjective: “The conference runs January 2–3”; “The Pulitzer Prize–winning journalists were applauded.” En-dashes are mandatory only for public documents. In internal or technical materials, use hyphens in their place.

Comma: In lists of three or more items, use a comma before and or or: “The recipe called for flour, butter, and foie gras.” When there are only two items, do not use a comma: “He doesn’t eat anything but pizza and Twizzlers.”

Period: Use only one space after the end of a sentence. Period.

Colon: Capitalize the first word after a colon only if it’s followed by a complete sentence: “The fact was undeniable: He was the only person still at work.” Otherwise, the first word is lowercase: “She loved only one thing: copyediting.”

Apostrophe: An apostrophe is used with contractions and also to indicate possession. Add an s to all single nouns and names, even if they already end in an s: “My boss’s vacation begins tomorrow.” The exception is if the noun or proper name itself is a plural: “The Pentagon Papers‘ release was controversial.”

Quotation marks: Periods and commas go inside quote marks. “Reginald, your hairstyle makes me nervous,” she said.” The position of exclamation and question marks depends on what’s being questioned or exclaimed: “Was she right to say, ‘Your shoes are a joke’?”

Capitalization and titles

Works: Things such as books, movies, paintings, and so on get title style capitalization and are italicized in text: “He couldn’t put down The Chicago Manual of Style.” “Her favorite album was Love Is Hell.”

Individuals: Capitalize a person’s title only if it precedes his or her name and isn’t modified: “Chief Executive Officer Leon Redbone”; “Leon Redbone, chief executive officer of Swizzle Stick, Inc.”

Everything else: When in doubt, use sentence-style capitalization and roman type. This applies to Web site buttons, press releases, and most PowerPoint decks.


Capitalize the first word after each bullet or number. Insert a period at the end of each item only if it’s a complete sentence, or if the list has a mix of complete and incomplete sentences.

The Internet

The words Internet and Web are capitalized: “Her Web site is full of curious links”; “Their Internet-access speed was excellent.” Note, however, that usage is changing, and it is likely that Web will soon become lowercase and Web site a single word. (The AP Stylebook already considers website to be a single word.)

URLs: In general-purpose text, addresses are given in the same typeface as the text in which they appear: “The address is”

Web sites: Use title-style capitalization and roman type: “He loves the Journalist’s Resource.”

Tags: capitalization, punctuation

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