AP Style vs Chicago Title Capitalization
Content owner: | Content reviewed: August 8, 2026 | Review standards
AP and Chicago agree on the core principle: capitalize the first and last words and the major words in a title. The visible differences come from how each guide handles prepositions, hyphenated compounds, and the choice between title case and sentence case.
Why older charts conflict: Chicago changed this rule in the eighteenth edition. Chicago 17 lowercased prepositions regardless of length. Chicago 18 capitalizes prepositions longer than four letters. If a chart says Chicago lowercases every preposition, it is describing the previous edition.
AP vs Chicago at a glance
| Question | AP title case | Chicago 18 title case |
|---|---|---|
| First and last word | Capitalize | Capitalize |
| Nouns, pronouns, verbs, adjectives, adverbs | Capitalize | Capitalize |
| Prepositions | Capitalize at 4+ letters | Capitalize at 5+ letters |
| Articles: a, an, the | Lowercase unless first or last | Lowercase unless first or last |
| Coordinating conjunctions | Lowercase short conjunctions | Lowercase common coordinating conjunctions |
| "to" in an infinitive | Lowercase | Lowercase |
| News headlines | Often sentence case by publication choice | Chicago's title rules primarily address titles of works |
The preposition rule with examples
Four-letter prepositions
AP: Gone With the Wind
Chicago 18: Gone with the Wind
Five-letter prepositions
AP: Travel Under the Stars
Chicago 18: Travel Under the Stars
Long prepositions
AP: The Space Between Us
Chicago 18: The Space Between Us
First or last position
Both styles capitalize a word at the beginning or end of a title, even when that word would normally be lowercase.
Draft a clean title case versionUse the case converter, then apply the AP or Chicago preposition rule above.
Open case converter →Hyphenated compounds
Hyphenated words need more judgment than a simple length rule. AP generally capitalizes each principal part. Chicago considers the role of each element, so short articles, prepositions, and conjunctions inside a compound can remain lowercase.
How-to
AP: A How-To Guide
Chicago: A How-to Guide
Mother-in-law
AP: Mother-in-Law
Chicago: Mother-in-Law
When a publication has a house style for compounds, use that instruction first. Automated converters are useful drafts, but they cannot always determine whether a word is acting as a preposition, adverb, or part of a proper name.
Title case or sentence case?
AP style does not require every newsroom or organization to display every headline in title case. Many publishers use sentence case for headlines: capitalize the first word and proper nouns, then lowercase the remaining words. Chicago's title-capitalization rules are commonly used for books, chapters, articles, and other named works.
Title case
How Small Teams Build Better Reports
Sentence case
How small teams build better reports
Which style should you use?
Choose AP
Use AP when you write for a newsroom, press office, public-relations team, or organization whose house guide names AP.
Choose Chicago
Use Chicago for book publishing, long-form editorial work, and organizations whose house guide follows the Chicago Manual.
If no style is required, choose one system and document the choice. Consistency across the same publication matters more than switching rules from title to title.
Job titles and geographic terms
Both systems distinguish a formal title attached to a name from a generic job description. For example, President Maya Chen uses a formal title before a name, while Maya Chen, the president uses a descriptive title. Both also lowercase compass directions used for movement and capitalize recognized regions, such as the Midwest.
Frequently asked questions
Is "with" capitalized in AP style?
Yes in AP title case because with has four letters. A publisher using sentence case would still lowercase it unless it begins the title.
Is "with" capitalized in Chicago style?
No. Chicago 18 capitalizes prepositions longer than four letters, so the four-letter word with remains lowercase unless it begins or ends the title.
Did Chicago change its capitalization rules?
Yes. The eighteenth edition changed the treatment of longer prepositions. Chicago 17 lowercased prepositions regardless of length; Chicago 18 capitalizes prepositions of five letters or more.
Primary references
- Chicago Manual of Style, 18th edition preface - explains the updated treatment of prepositions longer than four letters.
- Chicago title-capitalization Q&A - background on prepositions in titles.
- AP Stylebook current-edition information.