Check-in vs. Check In
“Check-in” is the hyphenated noun for registration or the place/process where it happens. “Check in” is the two-word phrasal verb used when someone registers or reports arrival.
Use “check-in” as the noun for the act, process, or place of registering arrival. Use “check in” as the verb, as in “Please check in online.”
Key details
Choose the right form
| Meaning / situation | Construction | Decision |
|---|---|---|
| act, process, time, desk, or place of registering arrival | check-in | use the hyphenated noun |
| register arrival or report status as a verb | check in | use the open phrasal verb |
Quick tests
Part-of-speech test
Is the expression functioning as a noun naming the registration process/place/time?
If yes: Use “check-in.”
If no: If it is the verb meaning register or report, use “check in.”
Caveat: Some branded interfaces may choose house styling, but ordinary prose should keep noun and verb roles distinct.
Examples
Online check-in opens 24 hours before departure.
The expression is a noun.
Please check in before going through security.
The expression is a verb.
We will check-in at noon.
Better: We will check in at noon.
As a verb in ordinary prose, write “check in.”
Further guidance
Core difference
Use the documented noun or modifier form when naming a thing, result, person, or concept; use the spaced form when the words function as a verb.
Fast Test
If the expression can take ordinary verb tense or inflection in the sentence, the spaced verb form is usually the relevant choice.
Variant Boundary
Cambridge places the hyphenated noun “check-in” and the two-word phrasal verb “check in” in the same entry, making the word-class boundary explicit.
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.
- CHECK IN — English meaning (opens in a new tab)Cambridge Dictionary · Hyphenated noun “check-in” and two-word phrasal verb “check in”