Chicago Title Capitalization Rules

CMOS 17 capitalises all major words. Short prepositions (≤4 chars) are lowercase, but longer ones like "About" and "Between" are capitalised.

Where Chicago Style Is Used

Chicago title capitalization is the standard for Books, Publishing, History, Arts & Humanities writing. Following the correct style guide is important when submitting work for publication, academic review, or professional presentation in these fields.

Chicago Capitalization Rules

• Capitalise all major words
• Lowercase: articles (a, an, the)
• Lowercase: coordinating conjunctions (FANBOYS)
• Lowercase: prepositions ≤4 letters (at, by, for, in, of, on, to)
• Capitalise: prepositions ≥5 letters (About, Above, Between…)
• Always capitalise first and last word
• Capitalise both parts of a hyphenated compound

How Chicago Style Works in Practice

Chicago title case is defined by the Chicago Manual of Style, 17th edition (2017), and is the standard for book publishing, academic monographs, history writing, and general non-fiction. Chicago uses a preposition-length rule: prepositions of four letters or fewer (at, by, for, in, of, on, to, up, with, from, into, over) stay lowercase, while prepositions of five or more letters (About, Above, Across, After, Among, Between, Beyond, During, Through, Without) are capitalized. This makes Chicago distinctly different from APA and MLA, which lowercase all prepositions. A title like "A Study About the World" capitalizes "About" in Chicago but not in APA.

Common Edge Cases in Chicago Style

• "With" has exactly 4 letters — it stays lowercase in Chicago even though it looks substantial.
• "Into" (4 letters) stays lowercase. "Until" (5 letters) gets capitalized.
• Coordinating conjunctions "so" and "yet" — Chicago capitalizes these when they function as adverbs, not conjunctions.
• First and last word are always capitalized, even if they are short prepositions like "of" or "in."
• The first word after a colon is always capitalized. The second part of a subtitle starts with a capital.

Example: Chicago Title Case

To see Chicago style applied to your own title with a word-by-word explanation of every rule, use the Chicago title capitalizer. You can also compare all 9 styles side by side using the same title.

How Chicago Differs From Bluebook

Chicago and Bluebook produce nearly identical title case because Bluebook's rules closely follow Chicago's preposition-length threshold. Both capitalize prepositions of five or more letters and lowercase shorter ones. The main practical differences appear in citation formatting rather than in title case itself. Bluebook adds legal-specific rules for case names, statutes, and abbreviations, while Chicago is the broader publishing standard. For general title capitalization of headings and article titles, the two styles are interchangeable.

See the full comparison in the Bluebook style guide or use the side-by-side comparison tool.

How Chicago Differs From Other Styles

Every style guide makes different choices about prepositions, articles, and conjunctions. Here is how Chicago compares to the other major title capitalization standards:

• APA — widely used in social sciences.
• AP — the standard for journalism and news.
• MLA — standard for literature and language.
• Bluebook — used in legal writing and law review.
• AMA — standard for medical and health writing.
• NY Times — used in one of the world's most read publications.
• Wikipedia — sentence case with proper nouns.
• Email — sentence case for professional communication.

Frequently Asked Questions

What is Chicago title capitalization?

Chicago title capitalization follows the Chicago Manual of Style, 17th Edition (CMOS 17). It capitalizes all principal words and lowercases articles, coordinating conjunctions, and prepositions of four or fewer letters. Prepositions of five or more letters — "About," "Above," "Between," "Through," "Without" — are capitalized.

When should I use Chicago title case?

Use Chicago title case for books, book chapters, journals, magazines, and academic work in history and humanities. Most US publishers, including university presses, follow the Chicago Manual of Style.

What words are capitalized in Chicago titles?

Principal words — nouns, pronouns, verbs, adjectives, adverbs, subordinating conjunctions — are capitalized. Longer prepositions (five or more letters) like "About," "Above," "Across," "Against," "Between," "Through," and "Without" are also capitalized.

What words are lowercase in Chicago title case?

Articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, so, yet), and prepositions of four or fewer letters (at, by, for, in, of, on, to, up, via, with, from, into, onto, over, down, like, than) are lowercase in the middle of a Chicago title.

Are articles capitalized in Chicago title case?

No. Articles (a, an, the) are lowercase in the middle of a Chicago title. The exception: the first and last words of a title are always capitalized, so "A," "An," or "The" is capitalized when it opens or closes the title.

Are conjunctions capitalized in Chicago title case?

Coordinating conjunctions (and, but, or, nor, for, so, yet) are lowercase. Subordinating conjunctions (because, although, when, since, while, unless) are principal words and are capitalized in Chicago style.

Are prepositions capitalized in Chicago title case?

Short prepositions (four or fewer letters) are lowercase: at, by, for, in, of, on, to, up, via, from, into, like, onto, over, down, than, with. Longer prepositions (five or more letters) are capitalized: About, Above, Across, After, Against, Among, Between, Beyond, During, Except, Through, Under, Until, Without.

Is the first word always capitalized in Chicago titles?

Yes. The first word of a Chicago title is always capitalized, regardless of part of speech.

Is the last word always capitalized in Chicago titles?

Yes. The last word of a Chicago title is always capitalized, regardless of part of speech.

How is Chicago title case different from other styles?

Chicago's key distinction is capitalizing longer prepositions (5+ letters) like "About" and "Between," while APA lowercases all prepositions. AP capitalizes all 4+ letter words — so it capitalizes "from" and "with," which Chicago lowercases. MLA, like APA, lowercases all prepositions regardless of length.

Can I convert a title to Chicago style automatically?

Yes. Use the Chicago title capitalizer to convert any title and see a word-by-word explanation.

Can I compare Chicago with APA, AP, and MLA?

Yes. The Compare Styles tool shows all 9 styles side by side for any title you enter.

Can I use TitleCasePro for Chicago capitalization?

Yes. TitleCasePro follows CMOS 17 rules. Use the Title Capitalizer for single titles or the Batch Capitalizer for lists.

Use the Chicago Capitalizer

Ready to capitalize a title in Chicago style? The Chicago title capitalizer converts your title instantly and explains every word. For processing a list of titles at once, use the batch capitalizer with CSV or TXT import. To see your title in all styles simultaneously, use the style comparison tool.

Read our guide on Chicago style title case rules for a complete reference with examples from CMOS 17.