Warm-up vs. Warmup vs. Warm Up
“Warm up” is the phrasal verb. “Warm-up” is the established hyphenated noun for preparation before an activity, while Cambridge also records “warmup” as a noun variant.
Use “warm up” as the verb. Cambridge records “warm-up” as the noun and also documents closed “warmup” as a noun variant.
Key details
Choose the right form
| Context | Use | Decision |
|---|---|---|
| verb describing preparation or making something warmer | warm up | Use the spaced phrasal verb. |
| noun naming a preparatory activity | warm-up | Use the established hyphenated noun. |
| noun variant in a style that accepts it | warmup | The closed noun is also documented; follow house style. |
Quick tests
Word-class test
Is the expression acting as a verb or naming the preparatory activity?
If yes: Verb → “warm up”; noun → “warm-up,” with “warmup” also documented as a noun variant.
If no: Check the word class and the publication’s spelling style.
Caveat: The closed and hyphenated noun forms are documented variants; the two-word form remains the verb.
Examples
Athletes should warm up before the race.
The spaced form is the phrasal verb.
The coach led a short warm-up.
The hyphenated form is the noun.
The app includes a five-minute warmup.
The closed noun variant is also documented.
Further guidance
Core difference
“Warm up” is the phrasal verb. “Warm-up” is the established hyphenated noun for preparation before an activity, while Cambridge also records “warmup” as a noun variant.
Fast Test
Choose by meaning, grammatical function, and documented regional convention rather than treating every visible variant as an error.
Variant Boundary
The verb stays open as “warm up”; the noun is “warm-up,” with “warmup” also documented as a noun variant.
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.
- WARM (someone/something) UP — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Phrasal verb “warm up”; noun “warm-up” with documented “warmup” variant