Many writers and editors ask whether "check in" should appear as a hyphenated term. The short answer depends on how the phrase is used in your sentence.
This guide explains when to hyphenate "check in," compares formats for booking scenarios, and clarifies grammar rules with real examples.
| Usage | Hyphenated | Not hyphenated | Example |
|---|---|---|---|
| Verb phrase | No | check in | Please check in at the counter. |
| Noun phrase | Yes | check-in | Complete the check-in process early. |
| Compound adjective before noun | Yes | check-in | You must follow the check-in instructions. |
| Title or heading | Yes | Check-in | Flight Check-in: Your Guide to a Smooth Start. |
Verb phrase check in
Asking someone to proceed
When you ask a passenger to move forward to the desk, you say "check in," with no hyphen, because it functions as a regular verb phrase.
Instructions at an airport
Staff often display signs saying "Check In Here," reminding travelers to complete procedures without a hyphen between the words.
Check in hyphenated as a noun
Desk and counter labels
Signs labeled "Check-in" or "Check-in Area" use a hyphen to turn the phrase into a clear noun referring to the location or process.
Formal documentation style
In policy documents or employee handbooks, "check-in" with a hyphen signals a defined activity, such as a regular check-in for performance reviews.
Comparison of formats for flight booking
Standard airline requirements
Most airlines distinguish between online actions like "check in" and physical spaces called "check-in desks," and the formatting should match each context.
Mobile app terminology
Booking apps often use "Check-in" as a capitalized screen title, while step by step buttons may show "Check In" without a hyphen to guide the action.
Grammar and style rules
Compound adjective use
Place a hyphen in "check-in time" or "check-in policy" because the term acts as a single descriptor before the noun it modifies.
Style guide consistency
Whether you follow AP, Chicago, or internal style rules, keeping "check in" and "check-in" usage consistent across a document reduces reader confusion.
Key takeaways for writers and editors
- Keep "check in" open when it is a verb phrase instructing action.
- Hyphenate "check-in" when it works as a noun or before a noun as an adjective.
- Review headings and labels to ensure they match standard usage and reader expectations.
- Maintain consistency across documents to strengthen clarity and brand tone.
FAQ
Reader questions
Should I write "check in" or "check-in" in an email to guests?
Use "check in" as a verb when asking guests to arrive early, and "check-in" as a noun when referring to the desk or the process.
Is "check-in time" hyphenated?
Yes, "check-in" is hyphenated here because it acts as a compound adjective describing "time."
Can I use "check in" as a noun without a hyphen?
No, when "check in" functions as a noun, such as a section of a form, it should be written as "check-in."
What if the style guide says "check in" only?
Follow the guide for verb contexts, but still apply "check-in" when the phrase modifies another noun or serves as a title.