Free HIIT Timer for iPhone

The simple, ad-free interval timer for high-intensity interval training

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What is HIIT?

HIIT (High-Intensity Interval Training) alternates short bursts of intense exercise with recovery periods. A typical HIIT session lasts15 to 30 minutes and can burn more calories than traditional steady-state cardio in less time.

HIIT works with any exercise: running, cycling, bodyweight movements, kettlebells, or gym machines. The key is pushing hard during work periods and recovering during rest. A reliable interval timer is essential to keep the structure tight.

Why Box Timer for HIIT?

• Flexible intervals — Set any combination of work time, rest time, and rounds. From quick 15-second sprints to longer 45-second circuits.
• Loud audio cues — Beeps at every transition so you know exactly when to push and when to rest, even with headphones off.
• Works with your music — Keep your workout playlist going. Timer sounds mix with your audio instead of cutting it off.
• Screen stays on — The display stays awake during your workout so you can always glance at the time remaining.
• Workout history — Sessions are saved automatically. Name and pin your go-to HIIT workouts for one-tap reuse.
• No ads, ever — No interruptions between rounds. No subscriptions. No premium tier. Just a timer.

How to set up a HIIT timer

1. Open Box Timer and tap Edit Timer
2. Select Interval as the timer type
3. Set Rounds to your desired number
4. Set Work time (e.g. 0 minutes and 30 seconds)
5. Set Rest time (e.g. 0 minutes and 15 seconds)
6. Turn on Countdown for a 10-second lead-in
7. Tap Save, then Start

See the full guide:How to set an interval timer with both work and rest time

Popular HIIT formats

All of these can be set up in Box Timer using the interval timer mode.

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Related:Free Tabata Timer for iPhone · Best Workout Timer Apps for iPhone in 2026 · HIIT & Interval Timer Guide