Title Case Converter
Capitalise headlines by a stated rule — AP style (short prepositions lowercase), Chicago style (all prepositions lowercase), sentence case or every word.
Titles capitalised consistently, one per line, with the words the rule lowered listed so an editor can see why “with” is capitalised in one style and not the other.
Example: “the art of war and peace: a guide to living with less” becomes “The Art of War and Peace: A Guide to Living With Less” in AP style and “…Living with Less” in Chicago style.
Which words
stay small.
The two headline conventions, exactly as the page applies them, and what it leaves alone.
AP and Chicago
Both conventions capitalise the first and last word and every “principal” word, and lowercase the articles (a, an, the) and coordinating conjunctions (and, but, or, nor, for, yet, so). They differ on prepositions: the AP convention lowercases only those of three letters or fewer (of, in, to, for…) and capitalises longer ones (With, From, Through); the Chicago convention lowercases all prepositions regardless of length. Both capitalise the first word after a colon or dash. The page applies these rules literally to a fixed list of prepositions and shows which words it lowered.
What is left as typed
Words in ALL CAPS (NASA, HTML, NASA's) are treated as acronyms and kept; words with an internal capital (iPhone, macOS, eBay) are kept; each part of a hyphenated word is capitalised (Real-Time). Sentence case capitalises only the first word and the first after a colon, lowercasing everything else except those protected words — which is why “The Art Of War” comes back as “The art of war”.
What it cannot know
The rules are mechanical. Style guides also ask you to capitalise a preposition used adverbially (“Look Up”), to keep proper nouns, and to judge phrasal verbs — none of which a word list can decide, so read the result before publishing it. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- The Associated Press Stylebook — composition titles: principal words capitalised; articles, conjunctions and prepositions of ≤ 3 letters lowercase unless first or last (convention, not reproduced)
- The Chicago Manual of Style, 17th ed., §8.159 — headline style: articles, coordinating conjunctions and all prepositions lowercase (convention, not reproduced)
Last reviewed 19 September 2026. How results are checked: How we verify.