Free Interval Timer for iPhone

The simple, ad-free interval timer for HIIT, CrossFit, Tabata, and boxing rounds

What is an interval timer?

An interval timer alternates between a work period and a rest period, repeated for a set number of rounds. It is the foundation of almost every structured training method — HIIT, Tabata, CrossFit EMOMs, and boxing all rely on interval timing to keep workouts organised and progressive.

Unlike a basic stopwatch or countdown, an interval timer handles the full workout automatically. Set your work time, rest time, and number of rounds once — then start the clock and focus entirely on training. Audio cues signal every transition so you never need to look at your phone mid-set.

Why Box Timer for interval training?

• Fully customisable intervals — Set any work time, rest time, and up to 99 rounds. From 10-second Tabata sprints to 5-minute boxing rounds.
• Work-only mode — Set rest to zero for EMOM-style workouts where the interval itself includes your rest.
• Loud audio cues — A long beep starts each work period. Three short warning beeps fire during the final seconds of rest so you are always ready to go.
• Large, readable display — Clearly shows the current round number, time remaining, and whether you are in a work or rest period. Rotate to landscape for a full-screen view.
• Works with your music — Interval beeps play alongside your playlist without cutting the audio.
• Saved interval presets — Every completed session is stored in history. Name and pin your most-used interval setups for instant recall.
• Free, no ads — No banners, no video ads, no subscription required. Every feature is available from the first launch.

How to set up an interval timer

1. Open Box Timer and tap Edit Timer
2. Select Interval as the timer type
3. Set Rounds to your desired number (e.g. 8)
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 before the first round
7. Tap Save, then Start

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

Popular interval timer setups

All of these can be configured in Box Timer using the interval mode in under a minute.

Related: Free HIIT Timer for iPhone  ·  Free Tabata Timer for iPhone  ·  Free Boxing Round Timer for iPhone  ·  HIIT & Interval Timer Guide