“because of” is a multiword expression whose title-case result depends on both style and how that style treats the words inside a phrase. Treat the expression as a phrase span while still applying the chosen style’s rule to each component rather than treating the phrase as one indivisible token.
ReviewedEvidence6 sourcesSectionWriting & Style
Quick answer
APA and Chicago 18: “Because of” internally. MLA: treat it as a multiword-preposition structure and keep current automated output gated until the current handbook rule is fully encoded.
Key details
Phrasebecause of
Rule Familymultiword-preposition-title-case
Termsbecause, of
Important caveats
Automation boundary
If the style requires unresolved grammatical or embedded-title analysis, leave the case unresolved rather than forcing an answer.
Phrase Boundary
Recognizing the phrase is useful, but phrase recognition alone does not override per-word style rules. Treat the expression as a phrase span, then apply the chosen style’s rule to each component.
Further guidance
Style Comparison
APA capitalizes “Because” as a major word and lowercases the short preposition “of.”
Chicago 18 capitalizes the long/major component “Because” and lowercases “of.”
MLA phrase-level handling is retained as a structural rule rather than guessed from word length alone.
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.
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.
MLA 9 describes title style as capitalizing the first word, last word, and all principal words. MLA’s public Style Center also documents the traditional lowercase treatment of internal prepositions, but its detailed preposition article is edition-labeled for MLA 8, so this engine does not yet treat the full MLA 9 converter profile as complete.
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.
“instead of” is a multiword expression whose title-case result depends on both style and how that style treats the words inside a phrase. Treat the expression as a phrase span while still applying the chosen style’s rule to each component rather than treating the phrase as one indivisible token.
“out of” is a multiword expression whose title-case result depends on both style and how that style treats the words inside a phrase. Treat the expression as a phrase span while still applying the chosen style’s rule to each component rather than treating the phrase as one indivisible token.
“according to” is a multiword expression whose title-case result depends on both style and how that style treats the words inside a phrase. Treat the expression as a phrase span while still applying the chosen style’s rule to each component rather than treating the phrase as one indivisible token.
“due to” is a multiword expression whose title-case result depends on both style and how that style treats the words inside a phrase. Treat the expression as a phrase span while still applying the chosen style’s rule to each component rather than treating the phrase as one indivisible token.
