Title Capitalization Style Guides
A quick-reference guide to the 9 major title capitalization styles — who uses them, what they capitalize, and how they differ.
APA
American Psychological Association — widely used in social sciences.
- Capitalise all major words (nouns, verbs, adjectives, adverbs)
- Lowercase: articles (a, an, the)
- Lowercase: coordinating conjunctions (and, but, or, nor, for, so, yet)
- Lowercase: prepositions (regardless of length)
- Always capitalise first and last word
- Always capitalise the word after a colon
Chicago
Chicago Manual of Style — standard for books and publishing.
- 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
AP
Associated Press — the standard for journalism and news.
- Capitalise words of 4+ letters
- Lowercase: articles (a, an, the)
- Lowercase: prepositions fewer than 4 letters
- Lowercase: coordinating conjunctions
- First and last word always capitalised
MLA
Modern Language Association — standard for literature and language.
- Capitalise all principal words
- Lowercase: articles (a, an, the)
- Lowercase: prepositions (all lengths)
- Lowercase: coordinating conjunctions
- First and last word always capitalised
- Capitalise both parts of hyphenated compounds
Bluebook
Bluebook citation — used in legal writing and law review.
- Capitalise all major words
- Lowercase: articles (a, an, the)
- Lowercase: coordinating conjunctions ≤4 letters
- Lowercase: prepositions ≤4 letters
- First and last word always capitalised
AMA
American Medical Association — standard for medical and health writing.
- Capitalise ALL words — no exceptions
- Articles, prepositions, conjunctions: all capitalised
- First and last word: capitalised (same as all other words)
- Hyphenated compounds: capitalise each part
NY Times
New York Times house style — used in one of the world's most read publications.
- Capitalise all principal words
- Lowercase: articles (a, an, the)
- Lowercase: prepositions ≤3 letters (at, by, in, of, on, to)
- Lowercase: coordinating conjunctions
- Capitalise prepositions ≥4 letters (With, From, Into…)
- First and last word always capitalised
Wikipedia
Wikipedia editorial policy — sentence case with proper nouns.
- Sentence case: only first word capitalised
- Proper nouns always capitalised
- Acronyms preserved as-is
- Word after colon capitalised
- All other words lowercase
Email subject line convention — sentence case for professional communication.
- Sentence case: only first word capitalised
- Proper nouns always capitalised
- Acronyms preserved
- All other words lowercase
- Conveys a professional, conversational tone
Why Title Capitalization Rules Differ
Each style guide was developed by a different organization for a different publishing context. The American Psychological Association (APA) created its rules for academic papers in social sciences. The Chicago Manual of Style (CMOS) was written for book publishing and general editorial work. The Associated Press Stylebook was designed for fast-paced newsroom journalism. Each set of rules reflects priorities specific to its field — consistency, readability, and the conventions expected by readers in that discipline.
The key differences come down to how each style handles prepositions, articles, and conjunctions. APA and MLA lowercase all prepositions regardless of length. Chicago lowercases only short prepositions (≤4 letters). AP capitalizes any word of 4 or more letters. AMA capitalizes every word with no exceptions. Wikipedia and Email use sentence case, where only the first word and proper nouns are capitalized.
Choosing the Right Style Guide
Use APA for psychology, social sciences, and education. Use Chicago for books, humanities, and general publishing. Use AP for journalism, news websites, and PR. Use MLA for literature and literary criticism. Use AMA for medical and health science journals. Use Bluebook for legal citations and law review articles. Use NY Times for editorial and newspaper headline style. Use Wikipedia for online reference and encyclopedia content. Use Email for professional and marketing email subject lines.
When your publication or institution has its own house style that modifies or extends one of these standards, apply the house style rules on top of the base standard. If you work across multiple styles, use the comparison tool to see how your title changes between styles.