Result
No. "Per" is a three-letter preposition ("Miles per Hour," "Posts per Week"), and every major style guide keeps it lowercase in the middle of a title. APA lists it by name among the short prepositions it lowercases.
"Per" by Style Guide
| Style guide | "Per" mid-title | Why |
|---|---|---|
| AP | Lowercase | Prepositions of three or fewer letters stay lowercase |
| APA | Lowercase | Short prepositions (three or fewer letters) stay lowercase |
| Chicago | Lowercase | Prepositions are lowercase at any length |
| MLA | Lowercase | Prepositions are lowercase at any length |
| AMA | Lowercase | Prepositions of three or fewer letters stay lowercase |
| Bluebook | Lowercase | Prepositions of four or fewer letters stay lowercase |
Examples in Chicago Style
- How Many Posts per Week
- Cost per Click Explained
- Words per Minute
- One Idea per Paragraph
"Per" is capitalized only at the start of a title or subtitle. Related: "via" is another short Latin-origin preposition with the same rule.
"Per" in Sentence Case
APA reference lists, many news sites, and most UI text use sentence case instead of title case. There, only the first word and proper nouns get capitals, so "per" is lowercase unless it starts the title: "How many posts per week." Pick one of the two styles for a whole set of headings rather than mixing them.
Quick Answers
Should "per" be capitalized in a title?
No. Every major guide keeps "per" lowercase mid-title.
Is "per" capitalized in APA?
No. APA lists "per" among the short prepositions it lowercases.