Multiword prepositions such as “according to,” “because of,” “instead of,” “out of,” and “up to” should not be handled by a single crude small-word list. Different style systems analyze components differently, and some phrases contain words that can change grammatical role.
ReviewedEvidence6 sourcesSectionWriting & Style
Quick answer
Recognize the phrase, then apply the relevant style’s component rules. Do not assume that every word in a multiword preposition must receive the same capitalization.
Key details
Reviewed Phrasesaccording to, because of, due to, instead of, out of, up to
Rule Familymultiword-preposition-title-case
Style-by-style guidance
Chicago 18
Chicago 18 treats title-case words component by component and now capitalizes prepositions of five letters or more; its current Q&A gives “The Gospel According to Matthew.”
Important caveats
Automation Policy
A recognized phrase span can add context and trace information; it is never allowed to convert an unresolved token from unsafe to safe on recognition alone.
Mla Boundary
MLA has public guidance specifically addressing two-word prepositions, but the public page is edition-scoped. This guide therefore keeps the current MLA named converter disabled until the current rule set is completely encoded.
Further guidance
Why Phrase Recognition Matters
Recognition prevents a converter from treating adjacent words as unrelated, but it is only one layer of the decision.
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.
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.
“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.
“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.
“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.
“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.
“up 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.
Hyphenated compounds cannot be capitalized safely with one universal “capitalize everything after a hyphen” rule. APA explicitly capitalizes the second part of hyphenated major words, while Chicago 18 changed its prefix-compound treatment and still applies grammatical title-case rules to individual elements.
