Interval timer for HIIT and Tabata

An interval timer you can read from across the room

This interval timer runs your work and rest periods for you. The time left is shown in very large digits, and the current interval is written out ("Work", "Rest") and colour-coded: red for work, green for rest. A bar shows your progress, with the "Total time left" underneath. Nothing is sent anywhere: saved workouts and history stay on your device.

How interval training works

You alternate short bouts of hard effort with recovery, several times over.

• Tabata: a protocol from a Japanese study in the 1990s. 20 seconds of very hard work, 10 seconds of rest, 8 times: 8 × 30 s = exactly 4 minutes.
• HIIT (high-intensity interval training): for example 30 s on and 30 s off, or 40 s on and 20 s off. With 10 rounds, each takes 10 minutes.
• EMOM (every minute on the minute): at the start of each minute you do a set number of reps, say 10 kettlebell swings, then rest until the next beep. "EMOM 10 min" gives ten one-minute rounds.
• Running intervals: the classic track or park session. The "Running intervals" preset has a 5-minute warm-up, 10 × 1 minute fast with 1 minute easy jogging, then a 5-minute cool-down: 30 minutes in all.

How to use it

1. Pick a preset or fill in the "Workout settings". Enter times as minutes:seconds (1:30) or seconds (90); 0 removes that interval.
2. Optionally, type your exercises under "Exercise names", one per line: the name appears in large type during work, and the next one shows during rest.
3. Click "Start" or press the space bar. "Pause" freezes the clock, "Resume" carries on from the same point, "Skip" and "Back" jump one interval.
4. "Full screen" enlarges the digits; "Keep screen on" stops your phone from going to sleep, where the device allows it.

"Beeps" sound on the last 3 seconds of every interval and again at the change, higher for work and lower for rest. "Voice" calls out "Work", "Rest" and the exercise name; "Vibration" buzzes your phone.

A custom workout, worked out

Warm-up 1:00, work 0:30, rest 0:15, 6 rounds, 2 sets, rest between sets 1:00, cool-down 1:00. Every work interval is followed by its rest, but at the end of the first set the rest between sets replaces the 15-second one. The maths: 12 work intervals × 30 s = 6 min, 11 rests × 15 s = 2 min 45 s, plus 3 minutes of warm-up, set break and cool-down. The timer shows "Total workout time: 11:45". With 4 exercises and 6 rounds, round 5 brings back the first one, and each set starts the list again.

Choosing times for your level

If you are new to this, rest longer than you work: 20 s on, 40 s off, 6 to 8 rounds. Then lengthen the work or shorten the rest, one change at a time, week by week. True Tabata is all-out; a steadier 20/10 is still a good workout. Save your formats under "My workouts".

Warm-up, cool-down and safety

A few minutes of easy movement gets your joints and breathing ready; a few calmer minutes at the end help you recover. Match the intensity to your fitness, stop if you feel pain, dizziness or unusual breathlessness, and check with a doctor if in doubt, especially when returning to exercise.

Frequently asked questions

Does the timer stay accurate if I switch apps?

Yes. Your position is recalculated from the start time: after 90 seconds in another tab, you are back on the right interval and time. On a locked phone, the system may mute the sound.

Can I change the settings mid-workout?

No, so the count is never thrown off. Click "Reset", make your changes, then start again.

Where are my workouts stored?

In the browser on this device. "History" lists completed workouts with date and length.

Why can't I hear the voice?

It relies on the voices installed on your device. If none is available, a message says so and the beeps carry on.