APA vs. Chicago vs. AP vs. MLA vs. AMA: Title Case, Compared

Why five different rule sets exist at all

Title case looks like one convention, but it is really a family of conventions maintained by different institutions for different audiences. The Publication Manual of the American Psychological Association (APA, now in its 7th edition) governs psychology, education and much of the social sciences. The Chicago Manual of Style serves book publishers and the humanities. The AP Stylebook is written for working journalists filing copy on deadline. The MLA Handbook (9th edition) covers literature and language scholarship, and the AMA Manual of Style (11th edition) rules medical and scientific journals.

Each guide optimized its capitalization rules for its own readers. Newsrooms wanted rules a sub-editor could apply in seconds; book publishers wanted typographic consistency across a 400-page work; academic publishers wanted rules that survive reference lists, running heads and databases. The result is five rule sets that agree on perhaps ninety percent of words — and disagree, loudly, on the rest.

What every style agrees on

Before looking at the differences, it helps to fix the common ground, because it covers most of every title you will ever write:

• The first word is always capitalized, whatever it is — even a, the or of.
• The last word is always capitalized, for the same reason: the edges of a title carry visual weight.
• Nouns, verbs, adjectives, adverbs and pronouns are always capitalized — including short verbs such as Is, Be and Go, which trip up more writers than any other rule.
• Articles are always lowercase in the middle of a title: a, an, the.
• Coordinating conjunctions are always lowercase in the middle of a title: and, but, or, nor, for, so, yet.
• The first word after a colon is capitalized — every major guide starts a subtitle with a capital.

If a word falls into any of those buckets, you can stop thinking. Every disagreement between the five guides lives in one part of speech: the preposition.

The preposition question: two camps

Ask the five guides what to do with with, from, under or between in the middle of a title, and they split cleanly into two camps.

The length-test camp reasons that a long word in lowercase looks like a mistake — readers expect a seven-letter word such as Between to be capitalized. The lowercase-all camp reasons that a preposition is a minor word doing minor work regardless of its length, and that grammar, not letter count, should decide the case. Neither side is wrong; they are just answering different questions.

One refinement worth knowing: Chicago and MLA also lowercase as in the middle of a title, and the length-test guides keep it lowercase anyway because it is under four letters — a rare point of accidental unanimity.

The same title in all five styles

Abstract rules become obvious with a worked example. Take the title the science of learning with others: a practical guide for teachers and run it through each rule set:

Everything except with is identical: The is capitalized as the first word, of and for are short prepositions and stay lowercase everywhere, a is an article, and A after the colon is capitalized by all five guides. The entire disagreement is that single four-letter preposition.

A second example shows the same split with more words involved — how to stay calm under pressure and lead through a crisis:

Note what does not change: to stays lowercase in every style (it is a short word even in the length-test camp), and stays lowercase as a coordinating conjunction, and the verbs Stay and Lead are capitalized everywhere. Once you can predict both rows of that table, you effectively know all five styles.

Style-by-style profiles

APA — psychology, education, social sciences

APA title case capitalizes the first word, the first word after a colon or em dash, all major words, and any word of four letters or more. It is the default for student papers across the social sciences, and — a nuance many people miss — APA uses title case for titles mentioned in the text and for headings, but switches to sentence case for titles in the reference list. If your APA reference list looks “under-capitalized,” it is probably correct.

Chicago — books, publishing, the humanities

Chicago is the publishing industry standard and the most conservative of the five: every preposition stays lowercase, however long. If you are preparing a manuscript, a book cover, or chapter titles for a publisher, Chicago is almost certainly what your editor expects.

AP — journalism and news headlines

AP style was built for headlines. It uses the same four-letter test as APA, which is why American news headlines capitalize With and From but not of or in. Note that many modern digital newsrooms have moved to sentence-case headlines entirely — but when a US outlet does use title case, AP rules are what you are seeing.

MLA — literature and the humanities classroom

MLA matches Chicago on the core question: all prepositions lowercase. It is the standard for literature and language-arts essays, and for works-cited lists in those fields. For a student essay title, MLA and Chicago will produce identical results in almost every case.

AMA — medicine and the sciences

AMA follows the length test like APA and AP, with the same three-letters-or-fewer cutoff for prepositions. Medical journal titles therefore look like APA titles in practice. The differences between AMA and APA live mostly in reference formatting, not in capitalization.

Which style should you use? A decision tree in words

1. Were you given a style guide? A journal, professor, employer or publisher that names a guide has answered the question for you. Follow it exactly — this is the one context where capitalization is graded.
2. Writing an academic paper? Psychology, education or social science → APA. Literature or humanities → MLA. Medicine or life sciences → AMA.
3. Writing news copy, a press release, or headlines for a US publication? → AP.
4. Writing a book, ebook, or anything a publisher will touch? → Chicago.
5. Writing for your own blog, newsletter or product? Pick either camp and stay consistent — or skip title case entirely and use sentence case, which is increasingly the default on the web. Our guide to sentence case vs. title case covers that decision in depth.

Consistency beats correctness

Here is the practical truth behind the whole debate: readers almost never notice which style you chose, but they reliably notice when you mix styles. A page that capitalizes With in one heading and lowercases it in the next reads as careless, even to people who could not name a single rule. So make the choice once, write it down, and automate it: our title case converter applies any of the five rule sets in one click, and the dedicated APA, Chicago, AP, MLA and AMA pages explain each style's quirks next to a live converter. When you hit a genuinely ambiguous word, the tricky cases guide walks through the edge cases one by one.

Frequently asked questions

What is the main difference between APA and Chicago title case?

Prepositions. APA capitalizes prepositions of four letters or more (With, From, Between), while Chicago lowercases every preposition regardless of length. The rest of the rules — first/last word, verbs, articles, conjunctions — are essentially identical.

Are AP and APA title case the same?

They produce the same result for most titles because both capitalize words of four or more letters, but they are separate guides for separate audiences: AP is for journalism, APA for academic writing in the social sciences.

Which title case style is most common?

Chicago is the default in book publishing, APA dominates academic writing in the social sciences, and AP rules US news headlines. For general web writing, Chicago and APA are the two most common defaults.

Do all five styles capitalize the first word after a colon?

Yes. APA, Chicago, AP, MLA and AMA all capitalize the first word of a subtitle after a colon, whatever the word is.

Keep reading

Try the tools