“Off” cannot be assigned one safe capitalization from spelling alone. As a short preposition it is normally lowercase internally in APA and Chicago, but as an adverb or verb particle it is a major word and is capitalized; the surrounding phrase determines the answer.
ReviewedEvidence3 sourcesSectionWriting & Style
Quick answer
Lowercase “off” when it is functioning as a short internal preposition; capitalize “Off” when it is an adverb or particle in a phrasal verb. This distinction matters in both APA-style major/minor-word logic and Chicago’s word-by-word grammatical treatment, so a trustworthy converter needs a POS override rather than a static small-word list.
Key details
APA 7lowercase as short preposition; capitalize as adverb/particle
Automation Classrequires POS override
Chicago 18lowercase as short preposition; capitalize as adverb/particle
Wordoff
Word Classpreposition, adverb, or particle depending on context
Important caveats
Fail Closed Rule
If the runtime cannot distinguish the role confidently, the named style mode should not silently force one answer.
Further guidance
Converter Test
Compare constructions such as “A Day off Work” with a phrasal-verb construction such as “Take Off Your Coat.” The surface token is the same, but the grammatical role differs.
Particle Or Adverb Use
When “off” functions adverbially or as the particle of a phrasal verb, it behaves as a major word and should be capitalized. Chicago explicitly treats words in multiword prepositional-looking expressions individually, as illustrated by its treatment of “Out” in “out of.”
Preposition Use
A short internal prepositional “off” belongs to the minor-word side of APA and Chicago title case.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
“To” is normally lowercase in the middle of titles under APA, Chicago, and MLA-style capitalization when it functions as a short preposition; Chicago also explicitly keeps “to” lowercase as an infinitive marker in ordinary mid-title position. Edge position can change the result.
Short words such as “up,” “out,” and “on” can change capitalization when their grammatical role changes. Chicago’s own examples capitalize “Up” or “Out” when those words function adverbially in a phrasal verb, while ordinary prepositional uses can remain lowercase.
Prepositions are one of the clearest places where title styles diverge. APA uses a four-letter major-word threshold, Chicago 18 capitalizes prepositions of five letters or more, and MLA editorial guidance generally lowercases internal prepositions regardless of length.
APA title case capitalizes the first word, the first word of a subtitle, major words, and words of four letters or more while keeping short minor words lowercase in ordinary mid-title positions.
Chicago 18 uses title case for titles of works and changed a long-standing rule: prepositions of five letters or more are now capitalized. Shorter prepositions generally remain lowercase internally, while first and last words are capitalized and “to” remains lowercase as an infinitive marker in ordinary mid-title use.
APA capitalizes “About” internally because it has at least four letters. Chicago 18 also capitalizes it when used as a preposition because current Chicago capitalizes prepositions of five letters or more. MLA treatment still depends on grammatical function, so prepositional and principal-word uses should not be collapsed into one rule.
APA capitalizes “Across” internally because it has at least four letters. Chicago 18 also capitalizes it when used as a preposition because current Chicago capitalizes prepositions of five letters or more. MLA treatment still depends on grammatical function, so prepositional and principal-word uses should not be collapsed into one rule.
APA capitalizes “After” internally because it has at least four letters. Chicago 18 also capitalizes it when used as a preposition because current Chicago capitalizes prepositions of five letters or more. MLA treatment still depends on grammatical function, so prepositional and principal-word uses should not be collapsed into one rule.
