"Title Case" sounds simple — capitalize the important words, lowercase the rest. The fight is over what counts as important. Two dominant style guides (AP and Chicago) disagree on small prepositions, and the disagreement matters just enough to confuse everybody.
The baseline rule
Both style guides agree on the basics:
- Always capitalize: the first word, the last word, nouns, verbs (including "is" and "be"), adjectives, adverbs, pronouns.
- Always lowercase: articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, yet, so) — unless they're first or last.
AP vs Chicago on prepositions
The split is on prepositions and the length threshold:
- AP style — lowercase prepositions of 3 letters or fewer ("of", "in", "on", "at", "to"). Capitalize 4-letter and longer ("With", "From", "Into").
- Chicago style — lowercase all prepositions regardless of length, unless used as adverbs. So Chicago writes "Notes from the Field" while AP writes "Notes From the Field".
Edge cases
- Hyphenated words — capitalize both parts ("Self-Aware", "Forty-Sixth"), unless the second half is a suffix ("Twenty-eight").
- "Is", "Are", "Be", "Am" — always capitalize. They're verbs, not prepositions.
- Quotation marks and parentheses — the first word inside them follows the same rules as a new sentence.
The pragmatic rule
Pick one style guide and stick with it for the document. Almost nobody notices which style you chose; everybody notices inconsistency within the same page. For most general writing, AP style is more common in US contexts and produces more lowercase words, which many editors find cleaner.
// TRY THE TOOL
TITLE-CASE ANY STRING.
Paste a string, pick Title Case, done. The tool follows standard article-lowering rules.
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