APA vs Chicago Title Case: What Is the Difference? | TitleCasePro
APA lowercases all prepositions; Chicago capitalizes those with 5+ letters. See the exact difference, side-by-side examples, and when to use each style.
Quick answer: APA and Chicago title case are nearly identical except for prepositions. APA lowercases all prepositions regardless of length; Chicago capitalizes prepositions of five or more letters (like About, Between, Through).
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:
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