15-Minute HIIT Timer
Fifteen minutes is where the ratio starts to matter. Three-to-one is hard enough to be worth the warm-up and forgiving enough that round twelve still looks like round two.
Worksec
45
Restsec
15
Rounds
15
Total 14:45
45 seconds on · 15 seconds off · 15 rounds · 14:45 of work and rest
What this timer runs
- Work
- 45 seconds
- Rest
- 15 seconds
- Rounds
- 15
- Work and rest
- 14:45
- Countdown
- 10 seconds before the first round
Every field above is editable — this is the free web timer, opened on one setting rather than an empty one. For what HIIT is and how to run it, HIIT Timer is the page above this one.
Questions
- How many rounds is a 15-minute HIIT session?
- 15, at 45 seconds of work and 15 of rest. That comes to 14:45 of work and rest; the ten-second countdown before the first round is what makes it 15 minutes on the wall clock.
- Can I change the intervals?
- Yes. The dial opens on this setting and every field is editable — change the work, the rest or the round count and the total updates as you type. Nothing is saved, and there is nothing to sign up for.
- Does it keep running if my screen locks?
- In the browser, not reliably — a phone that locks will stop the tab. That is what the iOS app is for: it keeps the clock and the spoken cues running in the background, and on the Apple Watch it taps your wrist at every switch.
Other lengths
- 5-Minute HIIT Timer30 seconds on · 30 seconds off · 5 rounds · 4:30 of work and rest
- 20-Minute HIIT Timer40 seconds on · 20 seconds off · 20 rounds · 19:40 of work and rest
- 30-Minute HIIT Timer45 seconds on · 15 seconds off · 30 rounds · 29:45 of work and rest
- 45-Minute HIIT Timer45 seconds on · 15 seconds off · 45 rounds · 44:45 of work and rest
Take it beyond the browser
Zestimer for iPhone and Apple Watch calls every switch with voice and haptics, turns YouTube workouts into timed sessions, and keeps your streak. Free on the App Store.
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