Chicago Versus AP — Who’s the Best?

After years of using the Chicago Manual of Style as my go-to style guide, I and the rest of the team will be using AP style in my upcoming fulltime gig. That being the case, I figured today would be a good day for a post explaining some of the major differences between the two, and which one might be the best.

Most general grammar and mechanics are treated the same way, but there are five major differences between the Chicago and AP styles that you (and I!) should be prepared to encounter on a regular basis.

Em Dashes and Ellipses

With regard to em dashes, Chicago style does not include a space on either side of them. AP style, on the other hand, does include a space before and after each dash.


Chicago: Best-selling authors—like Stephen King, Daniel Silva, and Kathryn Slaughter—are able to write an insane number of novels.

AP: Best-selling authors — like Stephen King, Daniel Silva and Kathryn Slaughter — are able to write an insane number of novels.

When using an ellipsis, Chicago style calls for three non-breaking-spaced periods with a space before and after the three. AP style, on the other hand, uses three periods, with a space before and after, but not between the periods.


Chicago: Darn it . . . why did you do that?

AP: Darn it … why did you do that?


In Chicago style, we spell out whole numbers up to (and including) one hundred. In AP style, we only have to spell out whole numbers up to (and including) nine. Note that both style guides have different rules for numbers in situations such as measurements, currency and percentages.


Chicago: Julio picked thirty-three oranges, but Darren picked just nine.

AP: Amy picked 23 apples, but Sally only picked eight.

Possessive Apostrophes

When you are using a noun ending in “s” that is possessive, do you use apostrophe-s or just an apostrophe? It depends on who you ask, and it depends on the kind of noun in question.

For singular common nouns that end in “s,” both Chicago and AP styles use apostrophe-s. Unless, that is, the following word begins with “s.” Then AP style calls for just an apostrophe. If the common noun is plural, both styles use just an apostrophe.


Singular common noun

Chicago and AP: Massachusetts’s rivers

AP only: Massachusetts’ streams

Plural common noun

Chicago and AP: The ladies’ hats

Proper nouns

In Chicago style, use an apostrophe-s if singular and just an apostrophe if plural. Use just an apostrophe if following AP style. 


Chicago: Hank Williams’s hat or the Millers’ house

AP: Sarah Cleamons’ eyes

Serial Comma

Also called the “Oxford comma,” this term refers to a comma that separates the penultimate item in a list from the final item introduced by a conjunction (“and” or “or”). In this situation, Chicago style uses a comma, while AP style does not.


Chicago: Hansel bought lard, bacon, and flour.

AP: Gretel bought flour, lard and bacon.

Titles: Quotation Marks or Italics?

Chicago uses italics for some titles and quotation marks for others, while AP only uses quotation marks for titles. Both style guides do have nuances for different types of titles, so we recommend checking the official books/sites for specific rules. For titles of larger works like books and movies, Chicago style uses italics, but AP style employs quotation marks.


Chicago: The Wizard of Oz

AP: “The Wizard of Oz”

Whichever style your organization follows, make sure to keep a copy of the guide on hand if you’re unsure about usage.

Different Style Guides for Different Writing Styles

It really can’t be stated that one is better than the other. The Chicago Manual of Style and the AP Stylebook are both written for the writing arena but directed at two different sets of users.

Chicago style is much more detail-oriented toward the actual nuts and bolts of manuscript and long-form article construction, including how to correctly cite other sources than your own work. In book and long-form article writing, the creator has weeks, months or years to get every detail correct and the Chicago style reflects that high level of craftsmanship.

AP style concentrates on being a general guide to news and public relations writing to help the writer and editor avoid potentially embarrassing mistakes in large distribution work. In news or digital media, deadlines and the need to publish immediately demand a much more “rough and ready” guide that sets general guides and relies on the individual writer’s talent and the editor to make sure the details come out right.

There isn’t a sure winner in the big AP versus Chicago style debate because they fill different needs. Each is a winner in its own way!