Split Infinitive
Modern editorial guidance does not support a blanket ban on split infinitives. Chicago accepts them and notes that splitting can improve clarity, emphasis, or euphony, while UC San Diego similarly accepts a split when it helps meaning or readability and advises against awkward placement.
A split infinitive places material—usually an adverb—between “to” and the base verb, as in “to clearly explain.” It is not categorically wrong; keep or avoid the split according to clarity, emphasis, rhythm, and the governing style.
Key details
Important caveats
Scope Boundary
This is partly a style decision, not a universal grammatical prohibition. Follow a controlling house style when one applies.
Further guidance
Application
If moving the adverb creates ambiguity or stiffness, the split may be the clearer choice. If the split sounds awkward and another placement is equally clear, revise it.
Core Rule
Do not rewrite a split infinitive automatically. Judge whether the adverb’s position makes the intended modification clearer and the sentence more natural.
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.
- Split Infinitives — CMOS Q&A (opens in a new tab)The Chicago Manual of Style · Style authority explaining that split infinitives are not categorically prohibited and can improve clarity, emphasis, or euphony.
- Editorial Style Guide — Split infinitives (opens in a new tab)University of California San Diego · Institutional editorial guidance accepting split infinitives when useful for meaning/readability and discouraging awkward placement.