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.
These distinctions may seem minor for a single word, but they compound across a full title or bibliography. A title containing "between", "through", and "about" will look visibly different in APA, Chicago, and AP style because each style treats those prepositions differently. Knowing the rules for your required style — and applying them consistently — is the difference between professional-quality work and casual writing.
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. If you regularly convert titles in a specific style, each style guide has its own dedicated capitalizer page accessible from the "Use tool" links above.
Compare Specific Styles
How to Use the Style Guide Tools
Each style guide entry on this page links to two resources. The "Read rules" link opens a full reference page with the complete set of rules, use cases, edge cases, and examples for that style. The "Use tool" link opens the interactive capitalizer pre-loaded with that style — paste a title and see it converted in real time with a word-by-word rule explanation.
If you work with multiple styles, the style comparison tool is the fastest way to see one title formatted in all nine standards simultaneously. For converting a spreadsheet or list of titles, the batch title capitalizer accepts CSV and TXT input and exports clean results. For text case beyond titles, the case converter handles 13 formats from UPPERCASE to snake_case.
Style Guide FAQ
Common questions about title capitalization style guides.
Title capitalization style guides are editorial manuals published by professional organizations — such as the American Psychological Association (APA), the University of Chicago Press (CMOS), the Associated Press, and the Modern Language Association (MLA) — that define rules for which words to capitalize in titles, headings, and references.
Different organizations developed their own standards for different audiences and purposes. Academic publishers prioritize consistency across long reference lists. Journalism prioritizes readability on deadline. Legal writing prioritizes precise citation format. Each guide's rules reflect the needs of its specific field.
TitleCasePro covers APA (7th Edition), Chicago Manual of Style (CMOS 17), AP Stylebook, MLA Handbook (9th Edition), Bluebook (21st Edition), AMA (11th Edition), NY Times, Wikipedia, and Email. Nine style guides in total.
APA title case capitalizes the first word, the first word after a colon, and all major words — nouns, verbs, adjectives, adverbs, and pronouns. All prepositions, articles, and coordinating conjunctions are lowercase regardless of their length. Used in psychology, education, and social sciences.
Chicago title case (CMOS 17) capitalizes all major words and lowercases articles, coordinating conjunctions, and prepositions of four or fewer letters. Longer prepositions like "About," "Between," and "Through" are capitalized. Standard for books, long-form publishing, and humanities.
AP title case capitalizes all words of four or more letters. Articles, prepositions shorter than four letters, and coordinating conjunctions are lowercase. This simple length-based rule is easy to apply consistently across deadline-driven journalism and news writing.
MLA title case capitalizes all principal words — nouns, pronouns, verbs, adjectives, adverbs, and subordinating conjunctions. Articles (a, an, the), all prepositions regardless of length, and coordinating conjunctions are lowercase. Used in literature, language studies, and most undergraduate humanities courses.
Bluebook title case is used for secondary sources in legal citations — law review articles, books, and treatises. It follows a conservative approach similar to Chicago: articles, short prepositions (≤4 letters), and coordinating conjunctions are lowercase; all other principal words are capitalized.
AMA title case (11th Edition) capitalizes every word in a title without exception — including articles, prepositions, and conjunctions. Example: "The Role Of Cognitive Therapy In The Treatment Of Anxiety." Used in medicine, nursing, and allied health sciences.
NY Times title case is close to AP: words of four or more letters are capitalized. Articles, prepositions of three or fewer letters, and coordinating conjunctions are lowercase. Used for article headlines and section titles in The New York Times.
Wikipedia uses sentence case, not title case. Only the first word and proper nouns are capitalized in Wikipedia article titles. All other words — even major nouns and verbs — remain lowercase. This contrasts with every other style guide covered here.
Email subject capitalization typically uses sentence case: capitalize only the first word and proper nouns. Studies from major email marketing platforms suggest sentence-case subject lines feel more personal and natural, which can improve open rates compared to full title case.
Choose APA for social sciences, Chicago for books and humanities, AP for journalism and digital media, MLA for literature courses, AMA for medical writing, Bluebook for legal citations, NY Times for editorial journalism, Wikipedia for encyclopedic reference, and Email for professional subject lines.
Yes. The Compare Styles tool shows your title formatted in all 9 style guides simultaneously.
Yes. Each style guide page on TitleCasePro has a link to the dedicated capitalizer for that style. Paste your title, get the correct result, and click "Explain" to see a word-by-word breakdown of every capitalization decision — so you learn the rules as you use the tool.