When to use title case

Title case is not one thing — different style guides disagree about which small words stay lowercase. This guide explains the three most common conventions (AP, Chicago, MLA/APA) and when to use each.

AP style

Associated Press style is the shortest rule: lowercase articles (a, an, the), coordinating conjunctions (and, but, or, for, nor), and prepositions of 3 letters or fewer. Everything else is capitalized. First and last words are always capitalized.

Example input: the sound of silence in the valley Example output: The Sound of Silence in the Valley

Chicago style

Chicago lowercases all prepositions regardless of length — via, at, by all stay lowercase. Otherwise the rules match AP.

Example: a story as old as time becomes A Story as Old as Time.

APA style

APA (which also covers MLA for most purposes) uses a length rule: any word of four or more letters is capitalized, even if it's normally a "small word".

Example: walking through the woods becomes Walking Through the Woods.

Sentence style

Only capitalize the first word of each line. Useful for UI copy, button labels, and some publication styles that eschew title case entirely.

Acronyms and hyphenated compounds

Our converter preserves all-uppercase tokens of 2–6 letters (like NASA, JPL) and capitalizes each segment of hyphenated compounds (like Mother-In-Law). Both behaviors can be toggled in the options bar.