Title Case Rules: AP vs APA vs Chicago vs MLA, with Examples

Capitalize the first and last word of the title, the first word of any subtitle, and every noun, verb, adjective, adverb and pronoun. Lowercase a, an and the, the conjunctions and, but, or and nor, and short prepositions such as of, in, on and to, unless they start or end the title. That much is common to AP, APA, Chicago and MLA. The guides split over longer prepositions (with, from, about, between) and a few conjunctions (so, yet, if). The tables below show every difference with real titles, and the title case converter applies any of the four styles to your own titles.

The rules all four styles share

These rules hold whichever guide you follow:

1. First and last word: always capitalized, even if it is a minor word. The in “The Old Man and the Sea” and For in “Something to Live For” get capitals because of where they stand.
2. The first word after a colon is capitalized, because it starts a subtitle: “The Case for Open Data: What Cities Can Learn”.
3. Major words are capitalized whatever their length. A short word is not automatically minor. Is, Be, It, We and Are are verbs or pronouns, so they take a capital: “So You Want to Be a Writer”, “Where the Wild Things Are”.
4. Articles are lowercase in the middle: a, an, the.
5. Short coordinating conjunctions and short prepositions are lowercase in the middle: and, but, or, nor, for, of, in, on, at, by, to.

APA spells out the idea behind these rules: “major words” are “nouns, verbs (including linking verbs), adjectives, adverbs, pronouns, and all words of four letters or more”, and minor words are short conjunctions, short prepositions and articles.

Where AP, APA, Chicago and MLA differ

The real differences are about which prepositions and conjunctions count as minor:

Style guide	Prepositions lowercased in the middle	Conjunctions lowercased in the middle
AP (news)	Three letters or fewer (of, in, on, for, off, up)	Three letters or fewer (and, but, or, nor, for, so, yet)
APA 7th edition	Three letters or fewer (as, at, by, for, in, of, off, on, per, to, up, via)	Three letters or fewer, including as and if
Chicago 18th edition	Four letters or fewer (with, from, into, over, like); as in any role	The common coordinating conjunctions (and, but, or, nor, for)
MLA 9th edition	Every preposition, however long (about, between, through, without)	Coordinating conjunctions (and, but, or, nor, for, so, yet)

What each guide says, in its own words:

• AP Stylebook: “Capitalize the principal words, including prepositions and conjunctions of four or more letters,” and “Capitalize an article (a, an, the) or words of fewer than four letters if it is the first or last word in the title.”
• APA: capitalize “words of four letters or more (e.g., ‘With,’ ‘Between,’ ‘From’)” and lowercase “only minor words that are three letters or fewer”.
• Chicago: “Starting with the 18th edition of CMOS, prepositions of more than four letters are capitalized in titles.” Earlier editions lowercased prepositions “regardless of length”, which is why older books and websites still show between and according to in lowercase. Chicago also keeps as lowercase “in any grammatical function”.
• MLA: a preposition in the middle of a title “should be lowercased, no matter how many words compose it and no matter how long those words are”. MLA’s own example is The World according to Garp.

The four-letter words are the ones to watch. With, from, into, over and like are capitalized in AP and APA but lowercase in Chicago and MLA. Five-letter and longer prepositions (about, after, among, between, through, without) are capitalized in AP, APA and Chicago and lowercase only in MLA.

Side-by-side examples

These titles were run through the title case converter in each style. Words that differ are the prepositions and conjunctions discussed above.

Before	AP	APA	Chicago	MLA
a room with a view	A Room With a View	A Room With a View	A Room with a View	A Room with a View
notes from underground	Notes From Underground	Notes From Underground	Notes from Underground	Notes from Underground
one flew over the cuckoo’s nest	One Flew Over the Cuckoo’s Nest	One Flew Over the Cuckoo’s Nest	One Flew over the Cuckoo’s Nest	One Flew over the Cuckoo’s Nest
think like a scientist	Think Like a Scientist	Think Like a Scientist	Think like a Scientist	Think like a Scientist
much ado about nothing	Much Ado About Nothing	Much Ado About Nothing	Much Ado About Nothing	Much Ado about Nothing
a novel without a hero	A Novel Without a Hero	A Novel Without a Hero	A Novel Without a Hero	A Novel without a Hero
the gospel according to matthew	The Gospel According to Matthew	The Gospel According to Matthew	The Gospel According to Matthew	The Gospel according to Matthew
what if we tried again	What If We Tried Again	What if We Tried Again	What If We Tried Again	What If We Tried Again
small yet mighty	Small yet Mighty	Small yet Mighty	Small Yet Mighty	Small yet Mighty

Many titles come out the same in every style, because they contain only articles, short prepositions and major words:

Before	All four styles
the old man and the sea	The Old Man and the Sea
love in the time of cholera	Love in the Time of Cholera
so you want to be a writer	So You Want to Be a Writer
something to live for	Something to Live For
the case for open data: what cities can learn	The Case for Open Data: What Cities Can Learn

Hyphens, phrasal verbs and other tricky cases

Hyphenated words. APA capitalizes “the second part of hyphenated major words”, giving “Self-Report” rather than “Self-report”. Minor words inside a compound stay lowercase. The converter gives “A Step-by-Step Guide to Self-Report Surveys” in all four styles.

Phrasal verbs. In set up, turn off or dress up, the small word works as an adverb that belongs to the verb, not as a preposition, so it is capitalized. Chicago’s Q&A gives “What Will Grandma Dress Up Like?” as its example. A converter that works from word lists cannot tell the difference, so it gives “How to Set up a Home Office” and “Turn off the Lights”. Fix the small word by hand: “How to Set Up a Home Office”.

The same word in two roles. Chicago’s Q&A points out that “according” is a participle, not a preposition, which is one reason it now writes “The Gospel According to Matthew”. MLA treats according to as a two-word preposition and lowercases it. Expect your editor to have the final say in borderline cases like these.

Acronyms and brand names. NASA, iPhone and eBay keep their own spelling in a title. The converter leaves them as typed when Keep acronyms and brand names is ticked: “the NASA guide to the iPhone” becomes “The NASA Guide to the iPhone”. Text typed entirely in capitals is treated as shouting, so “THE GREAT GATSBY” becomes “The Great Gatsby”.

Which style to use, and where

Pick the guide your publisher, school or company names. If nobody names one:

Writing	Usual style	Note
News stories, press releases, many blogs	AP	Four-letter rule for prepositions and conjunctions
Psychology and social science papers	APA	Title case for the paper title and all headings
Literature and humanities papers	MLA	Prepositions always lowercase
Books and book-length manuscripts	Chicago	Prepositions of five letters or more capitalized since 2024

APA uses title case for the title of your paper, all heading levels, table and figure titles and titles of works mentioned in the text. Titles of works in an APA reference list use sentence case instead, “even if title case was used in the original work”: only the first word, the first word of a subtitle and proper nouns are capitalized. The sentence case converter produces that, and the guide title case vs sentence case explains when each format fits.

Whatever you choose, use one style throughout a document or a site. A page that mixes “Notes From Underground” and “A Room with a View” looks careless even if each title follows some guide.

Converting titles quickly

To apply these rules to a batch of titles:

1. Paste the titles into the title case converter, one per line.
2. Choose AP, APA, Chicago or MLA under Style guide. Each line is converted as a separate title.
3. Check the comparison table, which shows your first title in all four styles.
4. Read the result for phrasal verbs (Set Up, Log In) and fix those by hand.

If you need lowercase, UPPERCASE or sentence case as well, the case converter has all of them in one place; its title case option uses the APA rules. For web pages, turn the finished headline into a URL with the slug generator and check its length with the character counter.