APA Title Case Rules: Complete Style Guide

If you're writing a research paper, thesis, or anything in the social sciences, you're almost certainly using APA format. The Publication Manual of the American Psychological Association (7th edition) has specific rules for capitalizing titles and headings - and they're not quite the same as AP, Chicago, or MLA. Getting them wrong can cost you marks or undermine an otherwise polished manuscript.

This guide walks through every APA title case rule with real examples. And if you'd rather skip the manual checking, our free headline capitalizer handles APA style automatically.

What Is APA Title Case?

APA title case is the capitalization format defined by the American Psychological Association for use in academic papers, journal articles, and scholarly publications. The APA style manual is the dominant formatting guide in psychology, education, nursing, social work, business, and many other social science fields.

The 7th edition of the APA manual (published in 2019) clarified and refined the title case rules that earlier editions sometimes left ambiguous. If you learned APA formatting from an older edition, it's worth reviewing the current guidelines - several details have changed.

APA actually defines two different capitalization formats: title case and sentence case. Knowing when to use each is just as important as knowing the rules themselves.

APA's Two Capitalization Formats

Unlike AP or Chicago, which primarily use one capitalization approach, APA requires you to switch between two formats depending on where the text appears:

This guide focuses on title case since that's what you use for your own paper's title, all headings, and in-text references. The sentence case rules are much simpler - capitalize only the first word, the first word after a colon, and proper nouns.

The Official APA Title Case Rules

According to Section 6.17 of the 7th edition, APA title case follows these rules:

1. Capitalize the first word of the title or heading.
2. Capitalize the first word after a colon, em dash, or end punctuation in a heading.
3. Capitalize all "major" words - nouns, verbs (including linking verbs like "is" and "are"), adjectives, adverbs, pronouns, and subordinating conjunctions.
4. Capitalize words of four letters or more - this includes prepositions and conjunctions that are four or more letters long (with, from, between, about, etc.).
5. Lowercase articles (a, an, the), short conjunctions (and, but, or, nor, for, yet, so), and short prepositions (of, to, in, on, at, by, up) - unless they're the first word.

If you're familiar with AP style title case, you'll notice APA's rules are very similar. Both use the four-letter threshold for prepositions. The main differences are in where each format gets applied and some edge cases around hyphenated compounds.

Words You Always Capitalize in APA Title Case

These word types are always capitalized regardless of position:

Pay special attention to "not" - it's an adverb and is always capitalized in APA title case. Writing "Factors That Do not Affect Recall" is incorrect. It should be "Factors That Do Not Affect Recall."

Words You Keep Lowercase

Only a small set of words stay lowercase in APA title case, and only when they appear in the middle of the title (never at the beginning):

The keyword here is "short." As soon as a preposition or conjunction has four or more letters, it gets capitalized. "In" stays lowercase but "Into" gets capitalized. "Or" stays lowercase but "Over" gets capitalized. That four-letter line is clean and consistent.

The Four-Letter Preposition Rule

This is the rule that most students and researchers get wrong when they first encounter APA style. Many people assume all prepositions are lowercase in titles. That's actually the Chicago Manual of Style's approach. In APA, prepositions follow a clear length-based rule.

Here's how the four-letter rule works in practice:

The elegance of this rule is that you don't need to memorize which prepositions are "short" or "long." Just count the letters. Three or fewer? Lowercase. Four or more? Capitalize.

Tricky Cases and Exceptions

The basic APA title case rules handle 90% of situations. But academic writing often involves terminology and structures that create edge cases. Here are the ones that come up most often:

Hyphenated Compounds

This is where APA gets specific. In a hyphenated compound, capitalize both elements if they are major words. If the second element is a prefix or suffix that can't stand alone, or if it's an article, short preposition, or short conjunction, keep it lowercase. So you write "Self-Report Measures" (both are major words) but "Re-evaluation" (the prefix "Re" gets capitalized as the first element, but if it appeared mid-title as "re-evaluation" the lowercase would apply). The 7th edition clarifies: capitalize both words of a hyphenated major word in a title.

After a Colon or Em Dash

In APA style, always capitalize the first word after a colon in a title or heading, regardless of whether what follows is a complete sentence. This differs from AP style, which only capitalizes after a colon when a full sentence follows. So in APA: "Cognitive Therapy: A New Approach to Treatment" capitalizes "A" even though it's an article.

Latin and Scientific Terms

Species names follow their own rules regardless of title case. The genus is always capitalized and the species is always lowercase, even in titles: "Effects of Escherichia coli on Water Quality." Italicize them as you normally would.

Two-Letter Verbs

Words like "is," "be," "am," "do," and "go" are verbs, not prepositions or conjunctions. Even though they're short, they get capitalized. "What It Is to Be Human" - both "Is" and "Be" are capitalized. This trips up a lot of people who think "short word = lowercase."

Heading Levels

APA defines five heading levels, and they don't all use title case:

All five heading levels use title case in the 7th edition. Earlier editions used different formats for Levels 3-5, so if you're working from older notes, double check.

APA Title Case Examples

Here are real-world examples showing how APA title case applies to academic writing:

APA vs. Other Capitalization Styles

Students often confuse APA with other styles, especially when taking courses across disciplines. Here's how APA compares to the other major formats on the points that matter most:

The biggest practical difference: APA and AP share the same four-letter preposition rule, while Chicago style lowercases all prepositions regardless of length. So if you're switching between a psychology paper (APA) and a history paper (Chicago), your title capitalization will change even though the content might be similar.

Another key APA difference: reference list entries use sentence case, not title case. Many students capitalize reference list titles the same way they capitalize headings, but APA specifically requires sentence case there. Our headline capitalization tool supports both formats.

Common APA Title Case Mistakes

These are the errors that show up most often in student papers and manuscript submissions:

Quick Reference

Bookmark this for your next paper:

APA title case is one of the more straightforward styles once you've internalized the four-letter rule. If you're coming from Chicago, the adjustment is simple: start capitalizing long prepositions. And for everything else, our headline capitalizer handles APA formatting automatically - just pick APA from the dropdown and paste your title.