Title Case Converter — AP, Chicago & APA Rules Explained
Updated: May 2026
Title Case seems simple — capitalise the important words — but "important" is defined differently by AP Style, Chicago Manual of Style, APA and MLA. Knowing which rule applies to your context prevents embarrassing inconsistencies in published content, academic papers and UI labels.
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What is Title Case?
Title Case is a capitalisation style in which the first letter of most words in a heading or title is uppercased. The words that are typically not capitalised are short function words: articles (a, an, the), short prepositions (in, on, at, by, for, to) and coordinating conjunctions (and, but, or, nor, yet, so, for).
There is one universal exception: the first and last word of a title are always capitalised, regardless of their part of speech.
Correct Title Case examples:
- The Art of War — "The" is capitalised because it is the first word
- Gone with the Wind — "with" and "the" are lowercase in the middle
- How to Win Friends and Influence People — "to", "and" are lowercase
- A Guide to Writing for the Web — "A" is capitalised (first word); "to", "for", "the" are lowercase
AP Style vs Chicago Manual of Style
The two most referenced American style guides differ on which prepositions to capitalise.
- AP Style: capitalise all words of four letters or more, regardless of part of speech. So "with" (4 letters) is capitalised in AP Style, but "for" (3 letters) is not.
- Chicago Manual of Style: capitalise all words except short articles, prepositions and coordinating conjunctions — regardless of length. "Between", despite being 7 letters, is a preposition and stays lowercase in a headline position in Chicago style.
- APA Style: used in academic publishing. APA Title Case capitalises all major words: nouns, verbs, adjectives, adverbs and pronouns. Prepositions and conjunctions of fewer than four letters are lowercase.
- MLA Style: capitalise all words except articles, prepositions (regardless of length) and coordinating conjunctions.
For blog posts and web content, AP Style is the most common guide used by journalists and content marketers. For academic papers, follow the journal's specific instructions — usually APA or MLA. For book titles and long-form publishing, Chicago is the default.
Title Case vs Sentence case in UI design
A recurring debate in product design is whether to use Title Case or Sentence case for interface labels, button text, navigation items and page headings.
- Title Case (e.g. Save Changes, Create New Project) reads as more formal and is traditionally associated with desktop software and enterprise applications. Apple's macOS and many B2B SaaS products use Title Case for menu items and primary actions.
- Sentence case (e.g. Save changes, Create new project) feels more conversational and is the dominant choice in modern consumer apps and Google's Material Design. It is also easier to scan because the capitalisation pattern matches the surrounding text.
Neither is objectively correct. The choice should be made at design-system level and applied consistently across all UI surfaces. Mixing Title Case and Sentence case within the same application is the only clearly wrong approach.
Capitalisation edge cases
Several word types require special attention in Title Case:
- Hyphenated words: both parts are usually capitalised — Twenty-Four Hours. Some guides lowercase the second part if it is a short word — Well-being vs Well-Being. Chicago recommends capitalising all parts.
- Phrasal verbs: the particle is capitalised even though it looks like a preposition — Log In to Your Account, not Log in to Your Account.
- Brand names: always preserve the brand's own capitalisation — iPhone, eBay, even at the start of a sentence.
- Subtitles after a colon: the first word after a colon in a title is always capitalised regardless of part of speech — Design Systems: A Practical Guide.
Frequently asked questions
What is Title Case?
Title Case capitalises the first letter of most words in a heading. Short prepositions, conjunctions and articles are typically kept lowercase unless they are the first or last word.
Is "the" capitalised in Title Case?
"The" is not capitalised in the middle of a title under AP, Chicago and MLA style. It is capitalised only when it is the first word of the title.
What is the difference between Title Case and Sentence case?
Title Case capitalises most principal words. Sentence case only capitalises the first word and proper nouns — the same way a regular sentence is written.