Is "By" Capitalized in a Title?

Title capitalization guide

No in most style guides — "by" is lowercase in AP Style, Chicago Style, and MLA Style.

preposition

Capitalized in 2 styles

Lowercase in 8 styles

Title Case

Lowercase as a short preposition unless first or last word

AP Style

Lowercase — AP lowercases all prepositions

NYT Style

YES

Capitalized — NYT Style capitalizes prepositions

Chicago Style

Lowercase — two letters, under the four-letter threshold

MLA Style

Lowercase as a short preposition

APA Style

Sentence case — only first word and proper nouns

AMA Style

Lowercase — AMA follows AP-style preposition rules

BB Style

YES

Every word capitalized — no exceptions

Wikipedia Style

Sentence case — only first word and proper nouns

Sentence Case

Only the first word of a title is capitalized

The full answer

"By" is a two-letter preposition that stays lowercase in the middle of a title in AP Style, Chicago Style, MLA Style, and AMA Style. NYT Style and Billboard Style are the two common exceptions that capitalize it.

NYT Style capitalizes "by" as part of its convention of capitalizing most prepositions. This is one of the most visible differences between NYT Style and AP Style in practice.

"By" can also function as an adverb, as in "passing by" or "standing by." When it functions as an adverb rather than a preposition, it carries more independent meaning and is typically capitalized in title case.

Like all prepositions, "by" is capitalized when it opens or closes a title. A title beginning with "By" — common in byline-style titles or poetic works — correctly capitalizes the word.

"By" follows the standard pattern for short prepositions in title case. AP Style lowercases all prepositions regardless of length, while Chicago Style lowercases prepositions of four letters or fewer. At two letters, "by" falls into the lowercase category under both rules.