Style & Grammar
Title Case Rules Explained: How to Capitalize Titles Correctly
TextKit Guides · 10 min read
Title case looks simple — capitalize the important words — until you hit a real headline. Is “through” capitalized? What about “off”, “up”, or the second half of a hyphenated word? Does it change after a colon? The major style guides (AP, Chicago, APA) agree on about 90% of title case and politely disagree on the rest. This guide gives you the shared core rules, the differences that matter, and enough worked examples to capitalize any title with confidence. When in doubt, you can also run your headline through our case converter, which applies the standard rules automatically.
The core rules everyone agrees on
1. Capitalize the first word and the last word, always. Even if they are words that would normally stay lowercase: “The Theory of What We Live For”, “A River Runs Through It”. This first-and-last rule overrides everything below.
2. Capitalize all “major” words. That means nouns, pronouns, verbs (including short ones like “Is” and “Be”), adjectives, adverbs, and subordinating conjunctions such as “although”, “because”, “if”, “when” and “while” in Chicago style. “The Cat Is Out of the Bag” — yes, “Is” is capitalized because it's a verb.
3. Lowercase the “minor” words in the middle. Articles (a, an, the), coordinating conjunctions (and, but, or, nor, for, so, yet), and short prepositions (at, by, for, in, of, off, on, per, to, up, via) stay lowercase when they appear mid-title: “The Old Man and the Sea”, “Gone with the Wind”. Note that “with” is a preposition — it stays lowercase in strict AP and Chicago style even though it has four letters, a point many people get wrong.
Where the style guides disagree
Prepositions of four or more letters. This is the biggest fault line. Chicago lowercases all prepositions regardless of length, so “through”, “between”, “under” and “without” stay lowercase mid-title. AP capitalizes words of four letters or more, including prepositions, so AP writes “A Walk Through the Forest” where Chicago writes “A Walk through the Forest”. APA follows a similar four-letter rule to AP for its reference-list titles. Neither is “wrong” — consistency with your chosen style is what editors check.
“To” in infinitives. In “How to Train Your Dragon”, the “to” is part of an infinitive and Chicago and AP both keep it lowercase. But if “to” starts the title or follows a colon, it is capitalized like any first word.
Subtitles. The first word after a colon or dash is always capitalized, even if it is an article or preposition: “Dune: The Desert Planet”, “Eat, Pray, Love: One Woman's Search…”. Each side of a colon is treated as its own title.
Hyphenated compounds
Capitalize the first element of a hyphenated compound. For the second element, capitalize it if it is a major word or carries equal weight, and lowercase it if it is an article, preposition or minor modifier: “The State-of-the-Art Facility” (all elements capitalized because the compound functions as one adjective with major parts), “A Step-by-Step Guide” (all major words), but “The Mother-in-Law Diaries” follows the same logic, while a compound like “Run-in” keeps “in” lowercase in strict Chicago style. Temporary compounds spelled with a prefix (re-, pre-, anti-, non-) usually keep the second element lowercase unless it is a proper noun: “Re-examining the Evidence”, “The Anti-Hero Returns” (AP capitalizes “Hero” here as a noun — when unsure, treat a noun as major).
Proper nouns, brands and stylization
Names of people, places, organizations and works keep their capitalization: “iPhone” keeps its lowercase i even at the start of a title in most editorial styles because it is a brand's official stylization, and “eBay” at the start of a sentence is a famous exception to every rule. Quotations used as titles keep the capitalization rules of titles, not of the quoted sentence. When a title contains a complete sentence, style guides still apply title case to it rather than sentence case.
Title case vs. sentence case
Sentence case capitalizes only the first word and proper nouns: “How to capitalize titles correctly”. APA uses sentence case for article titles in reference lists, many tech companies (Google, Microsoft, Apple) use it for UI headings, and British publishing leans toward it more than American publishing does. Title case remains the default for book titles, film titles, headlines and headings in US media. If you are converting between them, do it deliberately — a document that mixes the two looks careless even when every individual heading is “correct” by some style.
Common mistakes to avoid
- Capitalizing every word. “The Lord Of The Rings” is not title case; it is capitalized case. The small words are what make title case look professional.
- Lowercasing short verbs. “Is”, “Are”, “Be”, “Has” are verbs and are always capitalized.
- Lowercasing the last word. The final word is capitalized no matter what it is: “…What We're Fighting For”.
- Forgetting the subtitle. The word after a colon restarts the rules — capitalize it.
- Mixing styles in one document. Pick AP, Chicago or APA and apply it everywhere, including your headings and your references.
Try it: paste any headline into the TextKit Case Converter and choose “Title Case” to apply these rules instantly — then adjust for your house style if needed.
The bottom line
Capitalize first and last words, all nouns, pronouns, verbs, adjectives and adverbs; lowercase articles, coordinating conjunctions and (style permitting) prepositions in the middle. Learn the one or two points where your style guide differs from the default, and your titles will look right every time.
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