Tabata Timer
Press Start: after the get-ready countdown it is 20 seconds all-out, 10 seconds rest – eight times. Three short beeps announce every switch, and the colour shows the phase from across the room.
How it is calculated
How the Tabata timer works
A Tabata block consists of 8 rounds of 20 seconds of work and 10 seconds of rest. The timer starts after an adjustable get-ready countdown (10 s by default), shows the time left in the current phase in large digits and colours the display: red for work, green for rest. Three short beeps sound in the last three seconds of each phase, a high tone marks the start of work and a low tone the start of rest, and a final signal ends the block. Several Tabata blocks in a row can be planned with “Sets” and a set break (60 s by default).
Worked example: 8 × 20 s work + 7 × 10 s rest = 230 s, i.e. 3:50 minutes; with a 10 s get-ready countdown, 4:00. Pure work time is 160 s. Two sets with a 60 s set break take 2 × 230 + 60 = 520 s (8:40) plus the countdown.
Origin: Izumi Tabata’s 1996 study
The protocol goes back to a study by Izumi Tabata and colleagues at the National Institute of Fitness and Sports in Kanoya, Japan, published in 1996 in Medicine & Science in Sports & Exercise. Seven subjects trained on a cycle ergometer five days a week for six weeks: seven to eight bouts of 20 seconds at about 170% of VO2max with 10 seconds of rest between each bout, to exhaustion. VO2max rose by 7 ml/kg/min and anaerobic capacity by 28%.
Honest notes
- In the study the rest comes between the bouts – so a block here has 7 rests and lasts 3:50. Many apps count eight full 30-second rounds and arrive at 4:00; the difference is the final rest.
- The study subjects were young, trained physical education students working far above a normal sprint. A 20/10 workout with burpees or squats is useful interval training, but not the same as the study protocol.
- The timer measures neither heart rate nor power. If you have a health condition, have not trained for a long time or are unsure, check with a doctor before doing high-intensity training.
A typical Tabata workout
- Warm up gently for 5–10 minutes.
- Pick one exercise (bike, rowing, squats, burpees, mountain climbers) or alternate two.
- Start the timer, work as hard as you can with good form for 20 seconds, breathe for 10.
- With several sets, use the set break to switch exercises, then cool down.
Technical details
The sequence is calculated from the elapsed time instead of counting second by second, so everything stays correct after switching tabs. The beeps are scheduled in advance on the browser’s audio clock (Web Audio API) and play on time even in a background tab. Where supported, the screen stays on during the workout (Screen Wake Lock API). All settings are part of the page address and can be passed on with “Share”. For free work and rest times, see the interval timer under related tools.
Frequently asked questions
How does Tabata work?
Eight rounds of 20 seconds of maximum effort and 10 seconds of rest, just under four minutes in total. That is how the 1996 study by Tabata et al. describes it – there at about 170% of VO2max on a cycle ergometer.
Is a Tabata workout 4 minutes?
Eight rounds of 20 s work and 10 s rest take 3:50 if the rest only comes between bouts, as in the study, or 4:00 if you count eight full 30-second rounds. With the get-ready countdown this timer shows 4:00 on the clock.
Can I use this Tabata timer on my iPhone?
Yes, it runs in Safari and every current browser. The ring/silent switch must be off for the beeps; the browser enables sound after you tap Start. Keep the page open – some phones pause audio when the screen is locked.
Can I do several Tabata rounds in a row?
Yes. Set “Sets” to 2 or more and choose a set break, for example 60 seconds. The timer then runs all blocks one after another and shows the current set.
Which exercises suit Tabata?
Exercises where you reach high intensity quickly and can stop immediately: cycling, rowing, squats, burpees, jumping jacks, mountain climbers. Good form comes before speed.
How often per week can I do Tabata?
The study trained five times a week, but with trained sports students. For most people 2 to 3 high-intensity sessions a week with rest days in between are plenty; if in doubt, ask a doctor.
Sources and legal basis
- Tabata I., Nishimura K., Kouzaki M. et al. (1996): Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Med Sci Sports Exerc 28(10), 1327–1330
- MDN Web Docs: Web Audio API
- MDN Web Docs: Screen Wake Lock API
As of:
Related tools
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- Online TimerFree online countdown timer: enter any time or tap a 5, 10 or 15 minute preset, get an alarm when time is up, remaining time in the tab. No sign-up.
- Heart Rate Zone CalculatorCalculate your training heart rate zones: enter your max heart rate or estimate it with Tanaka, then get zones as % of max HR or with the Karvonen method.
- Online StopwatchFree online stopwatch with lap times, fastest/slowest lap and copy-to-clipboard. Keeps running after switching tabs or reloading the page.
- Binaural beats generatorBinaural beats online: set carrier and difference frequency, a separate sine tone for each ear, with timer and headphone test. No health claims.
- BMI calculator (WHO categories)Calculate your body mass index in lb and ft/in or kg and cm. See your WHO category, from underweight to obesity class III, and the healthy weight range.