AP vs Chicago Title Case: How the Rules Differ
AP style and Chicago style agree on most of a title. Both capitalize the first and last words, the words on both sides of a colon, and nouns, verbs, adjectives, adverbs, and pronouns, and both lowercase the articles a, an, and the.
They split on prepositions of four letters, on the conjunctions if, so, and yet, and on the second part of a hyphenated compound. The examples below come from the AP and Chicago converters.
Side by side
| Input | AP style | Chicago style | What it shows |
|---|---|---|---|
| the man with the golden gun | The Man With the Golden Gun | The Man with the Golden Gun | "with" has four letters. |
| music from the heart | Music From the Heart | Music from the Heart | "from" has four letters. |
| The Quick Brown Fox Jumps Over The Lazy Dog | The Quick Brown Fox Jumps Over the Lazy Dog | The Quick Brown Fox Jumps over the Lazy Dog | "over" has four letters. |
| much ado about nothing | Much Ado About Nothing | Much Ado About Nothing | Both capitalize a preposition of five letters. |
| what dreams may come if we wait | What Dreams May Come if We Wait | What Dreams May Come If We Wait | "if" is a short conjunction. |
| slow and steady yet sure | Slow and Steady yet Sure | Slow and Steady Yet Sure | "yet" is a short conjunction. |
| a follow-up on the all-in bet | A Follow-Up on the All-In Bet | A Follow-up on the All-in Bet | Two-part hyphenated compounds. |
The rules compared
| Rule | AP style | Chicago style |
|---|---|---|
| Source | The AP Stylebook "composition titles" entry | The Chicago Manual of Style, 18th edition (2024) |
| Prepositions | Lowercase at three letters or fewer (at, by, in, of, off, on, per, to, up, via). Four letters or more are capitalized: With, From, Over. | Lowercase at four letters or fewer, from a list (with, from, into, over, upon). Five letters or more are capitalized: About, Between, According. |
| Conjunctions | Lowercase at three letters or fewer: and, as, but, for, if, nor, or, so, yet. That is capitalized. | Only and, but, for, or, and nor are lowercase, plus "as". If, So, Yet, and That are capitalized. |
| Two-part hyphenated compounds | Both parts are capitalized: Follow-Up, All-In. | The second part is lowercase when it is an article, short preposition, or coordinating conjunction: Follow-up, All-in, but Anti-Intellectuals. |
When to use each
AP style
News stories, press releases, and other writing that follows the AP Stylebook, for titles of books, movies, songs, and other works.
AP Style Title Case ConverterChicago style
Books, humanities papers, and publications whose house style is The Chicago Manual of Style.
Chicago Style Title Case Converter