Title Case Rules for APA, Chicago and MLA

Capitalizing an English title looks simple until you meet the details: Is with capitalized? What about between? Why do reference lists put article titles almost entirely in lowercase? Each style answers differently — and the Chicago Manual of Style changed its preposition rule in its 18th edition (2024), so a lot of advice online is now out of date.

This guide summarizes the rules of APA 7 (2020), Chicago 18 (2024) and MLA 9 (2021), checked against official sources in September 2026. To convert a title instantly, use the title case converter.

1. Title case and sentence case

In title case, major words start with a capital and minor words — articles, short prepositions and conjunctions — stay lowercase:

Train Your Mind for Peak Performance: A Science-Based Approach for Achieving Your Goals

In sentence case, you capitalize only what you would capitalize in a sentence — the first word and proper nouns — plus the first word of a subtitle:

Train your mind for peak performance: A science-based approach for achieving your goals

Chicago 18 renamed its "headline style" and "sentence style" to title case and sentence case; the concepts did not change.

2. APA 7: the four-letter rule

APA divides words into two groups.

Major words: nouns, verbs (including linking verbs), adjectives, adverbs, pronouns, and all words of four letters or more.
Minor words: short (three letters or fewer) conjunctions, short prepositions, and all articles.

In title case, capitalize the first word of the title and of any subtitle, the first word after a colon, em dash or end punctuation in a heading, and every major word. Lowercase only the minor words. APA's own examples of minor words are:

short conjunctions: and, as, but, for, if, nor, or, so, yet
articles: a, an, the
short prepositions: as, at, by, for, in, of, off, on, per, to, up, via

So in APA, With, From, Into and Between are capitalized — APA's own heading template reads "Ending With a Period." Short verbs and pronouns such as Is, Be and It are capitalized too. In hyphenated compounds, capitalize the second part if it is a major word: Self-Report, not Self-report; Well-Being.

Where APA uses each case

Context	Case
Titles of works mentioned in your text	Title case
Your paper's title and all heading levels	Title case
Periodical names	Title case, italic
Table and figure titles	Title case, italic
Titles of articles, books, reports and webpages in the reference list	Sentence case, even if the original used title case
Table column headings, entries and notes; figure notes	Sentence case

The reference list is where most errors happen. The article title goes in sentence case while the journal name stays in title case:

Scott, T. N., Gil-Rivas, V., & Cachelin, F. M. (2019). The need for cultural adaptations to health interventions for African American women: A qualitative analysis. Cultural Diversity and Ethnic Minority Psychology, 25(3), 331–341. https://doi.org/10.1037/cdp0000228

APA's sentence case also capitalizes nouns followed by numerals or letters (Experiment 2, Table 3). See the APA guide for full reference formats.

3. Chicago 18: prepositions of five letters or more are now capitalized

The core of Chicago's title-case rule (CMOS 18, 8.160):

Capitalize the first and last words of titles and subtitles.
Capitalize major words — nouns, pronouns, verbs, adjectives, adverbs.
Lowercase the articles a, an, the.
Lowercase prepositions of four letters or fewer; capitalize prepositions of five letters or more.
Lowercase the coordinating conjunctions and, but, for, or, nor.
Lowercase to (as a preposition or in an infinitive) and as in any grammatical function.

Rule 4 is new. Through the 17th edition, Chicago lowercased prepositions "regardless of length." Chicago's own examples of the new rule are A Room with a View but Much Ado About Nothing, and it now styles The Gospel According to Matthew.

Words that look like prepositions are capitalized when they act as adverbs or adjectives — Up in "Breaking Up Is Hard to Do" — or as conjunctions, as in Look Before You Leap. Chicago treats than as a preposition before a noun ("There Is More than One Path to a Successful Meal") and as a conjunction, capitalized, before a clause.

Note two contrasts with APA. Chicago's lowercase conjunctions do not include so and yet, so Chicago writes "Fast Yet Accurate." And four-letter prepositions that APA capitalizes (with, from, into) stay lowercase in Chicago.

For hyphenated terms, the 18th edition capitalizes elements after a prefix by the general rule: Anti-Intellectual Pursuits (the 17th edition had Anti-intellectual).

4. MLA 9: prepositions stay lowercase at any length

MLA's rule (MLA Handbook 9th ed., 2.90) is to "capitalize the first word, the last word, and all principal words." In the middle of a title, keep these lowercase:

articles: a, an, the
prepositions, whatever their length: of, with, between, during, according to
coordinating conjunctions: and, but, for, nor, or, so, yet
the to in infinitives

The MLA Style Center's examples show the pattern: "Errors Found during Testing," "How to Search the Web," and "The World according to Garp." An article that starts a subtitle is capitalized — The Sisters: The Saga of the Mitford Family — and the last word is always capitalized, so a title ending in etc. ends with "Etc." MLA uses sentence case for titles in languages other than English.

5. Word-by-word comparison

Word	APA 7	Chicago 18	MLA 9
a, an, the	lower	lower	lower
and, but, or, nor	lower	lower	lower
for	lower	lower	lower
so, yet (conjunctions)	lower	Cap	lower
if	lower	Cap	Cap
as	lower	lower	lower (preposition)
to	lower	lower	lower
of, in, on, at, by	lower	lower	lower
with, from, into, over	Cap	lower	lower
about, among, between, during	Cap	Cap	lower
than (preposition)	Cap	lower	lower
is, are, be, it, its	Cap	Cap	Cap
up, down, on used as adverbs	Cap	Cap	Cap

The same title in three styles:

Input	APA 7	Chicago 18	MLA 9
gone with the wind	Gone With the Wind	Gone with the Wind	Gone with the Wind
much ado about nothing	Much Ado About Nothing	Much Ado About Nothing	Much Ado about Nothing
errors found during testing	Errors Found During Testing	Errors Found During Testing	Errors Found during Testing
fast yet accurate estimation	Fast yet Accurate Estimation	Fast Yet Accurate Estimation	Fast yet Accurate Estimation

6. Exceptions that override the rules

Capitalization rules apply to ordinary words. Keep the established form of:

Acronyms and initialisms: DNA, COVID-19, fMRI — also in sentence case.
Brand names with lowercase initials: iPhone, eBay — never "IPhone."
Proper nouns and proper adjectives: Korea, African American, Bayesian — capitalized even in sentence case.
Species names: genus capitalized, species lowercase (Homo sapiens); Chicago keeps the species name lowercase even as the last word of a title.
Test names: APA puts test and measure names in title case (Beck Depression Inventory–II).

No automatic converter can reliably tell a preposition from an adverb, or spot every proper noun. After converting, check words like up, before and than, and every name and acronym.

7. Common mistakes

Leaving APA reference-list article titles in title case — switch to sentence case.
Converting journal names to sentence case — they stay in title case.
Lowercasing With or From in APA — four-letter words are capitalized.
Lowercasing About or Between in Chicago — since the 18th edition, prepositions of five or more letters are capitalized.
Lowercasing the first word after a colon — all three styles capitalize it.
Lowercasing short verbs such as Is or Be — verbs are always major words.
Flattening acronyms and proper nouns when converting to sentence case.

A journal's own author guidelines override all of the above; use the style rules to fill in whatever the journal does not specify.