AP, APA, Chicago and MLA in a few lines
All four agree on the principle: capitalize the important words, lower the small ones. They disagree about which words are small.
- AP and APA: articles (a, an, the), short conjunctions (and, but, for, nor, or, so, yet, if) and prepositions of up to three letters (as, at, by, in, of, on, per, to, via) stay in lower case. The exceptions are up, off and out, which are often adverbs in headlines and keep their capitals. Anything of four letters or more is capitalized. 'A Walk Through the Park' has a capital T in Through.
- Chicago and MLA: articles, coordinating conjunctions and prepositions stay in lower case, however long. 'A Walk through the Park' keeps through small, and so do with, between, despite and towards. Words that are prepositions only some of the time (inside, outside, near, past, like, down, off, out and up) keep their capitals here, because the converter cannot tell how you use them. Chicago and MLA are common in book publishing and the humanities, APA in the social sciences.
AP uses sentence case for its own news headlines, so its four letter rule applies to the titles of books, films and the like. If your school, publisher or employer names a guide, use that one. If none is named, any of them is acceptable as long as you use the same one everywhere.
What the converter handles for you
- First and last word. Capitalized whatever they are, so 'what are you up to' ends with To.
- After a colon. 'star wars: a new hope' becomes 'Star Wars: A New Hope'. A question mark, an exclamation mark, a dash and a full stop do the same, except after an abbreviation: 'mr. and mrs. smith' becomes 'Mr. and Mrs. Smith'.
- Hyphenated words. The first part is always capitalized and later parts follow the small word rule, which gives 'Up-to-Date' and 'Well-Known'.
- Apostrophes. don't becomes Don't, not Don'T.
- Acronyms, brands and links. NASA, iPhone, www.example.com and [email protected] are left as typed.
- Several titles at once. Every line is its own title, so a pasted list is converted line by line.
What it cannot know
A program sees letters, not meaning, so a few results need a human check:
- Particles that look like prepositions. In 'log in' and 'turn on', the small word belongs to a verb and many guides capitalize it. The converter lowers in and on every time, and always capitalizes up, off, out, down, inside, outside, near and past.
- The word to. It stays in lower case, as it should in an infinitive, but a guide may capitalize it in a phrasal verb.
- Proper nouns typed in lower case. 'paris' gets a capital as the first letter of a word, but a name such as 'van der Berg' may need its own treatment.
- Titles in other languages. The small word lists are English. French, German and Spanish titles follow different rules and are usually not set in title case at all.
For ordinary text rather than headlines, sentence case is usually the better style.