APA vs Chicago Title Case: What Is the Difference? | TitleCasePro

APA and Chicago are the two most commonly confused title case styles because they look almost identical on most titles. Both capitalize nouns, verbs, adjectives, and adverbs. Both lowercase articles and coordinating conjunctions.

The one difference that matters: APA lowercases all prepositions regardless of length. Chicago lowercases prepositions of 4 letters or fewer, but capitalizes longer ones (5+ letters).

Side-by-Side Examples

Title with “about” (5 letters — preposition)

Style	Result
APA	Writing about the Modern World
Chicago	Writing About the Modern World

Title with “between” (7 letters — preposition)

Style	Result
APA	The Relationship between Science and Faith
Chicago	The Relationship Between Science and Faith

Title with “through” (7 letters — preposition)

Style	Result
APA	Learning through Experience and Observation
Chicago	Learning Through Experience and Observation

Title with only short prepositions — identical in both styles

Style	Result
APA	A Guide to the Art of Writing
Chicago	A Guide to the Art of Writing

to (2 letters) and of (2 letters) are below the threshold in both styles — they stay lowercase everywhere.

The Preposition Boundary

Always lowercase in both APA and Chicago (≤ 4 letters)

at, by, for, in, of, on, to, up, as, via, per, off, out, into, from, over, with, like, onto, down, upon, near, past, than, till

Lowercase in APA, Capitalized in Chicago (5+ letters)

About, Above, After, Along, Among, Below, Since, Under, Until, While, Against, Around, Before, Behind, Beside, Between, Beyond, During, Except, Inside, Toward, Through, Within, Without

⚠️ The single most common error: Writers familiar with one style apply it to the other. If your institution requires APA, about and between must be lowercase. If it requires Chicago, they must be Capitalized.

Why the Two Styles Made Different Choices

The difference reflects two distinct editorial philosophies:

APA’s approach — grammatical consistency: The APA Publication Manual applies a consistent word-class rule. Prepositions as a grammatical category are all treated as minor words, regardless of length. This prioritizes logical consistency.

Chicago’s approach — visual judgment: The Chicago Manual of Style takes a more pragmatic approach. Short prepositions look minor in a title; long prepositions look major. A title like Learning Without Fear looks visually unbalanced with without in lowercase. Chicago resolves this by capitalizing any preposition long enough to look significant.

Neither approach is wrong — they reflect different values.

Quick Comparison Table

Rule	APA	Chicago
First and last word	Capitalize	Capitalize
Nouns, verbs, adjectives, adverbs	Capitalize	Capitalize
Pronouns	Capitalize	Capitalize
Articles (a, an, the)	lowercase	lowercase
Coordinating conjunctions	lowercase	lowercase
Prepositions ≤ 4 letters	lowercase	lowercase
Prepositions 5+ letters	lowercase	Capitalize
Infinitive to	lowercase	lowercase
First word after colon	Capitalize	Capitalize

Which Should You Use?

Use APA when:

• Writing a research paper in psychology, social sciences, education, or nursing
• Your institution or journal explicitly requires APA 7th Edition
• Submitting to an APA-formatted journal

Use Chicago when:

• Writing a book or book proposal
• Writing history, humanities, or literary criticism
• Your publisher, journal, or university press uses Chicago style

When neither is specified: Chicago is the safer default for formal non-academic writing. APA is the safer default for academic research in the sciences and social sciences. When in doubt, check with your instructor, editor, or the journal’s submission guidelines.

Try Both on Your Title

The fastest way to see the APA vs Chicago difference on your own title is the compare tool — paste your title once and see all nine style guides, including APA and Chicago, side by side.

For detailed rules and word-by-word explanations:

• APA title capitalizer
• Chicago title capitalizer
• APA vs Chicago style guide