What Tabata is: the 1996 protocol
Tabata training comes from a study by Izumi Tabata and colleagues (Medicine & Science in Sports & Exercise, 1996) on Japanese speed-skaters: 7–8 sets of 20 seconds at about 170% of VO2max with 10 seconds of rest, 4 minutes in all, performed four days a week for six weeks after a 10-minute warm-up, alongside one longer steady session. The group improved maximal oxygen uptake by about 7 ml/kg/min and anaerobic capacity by 28%, while a group doing 60 minutes of moderate cycling improved VO2max by a similar 5 ml/kg/min but gained no anaerobic capacity.
The result that made the name famous is that four minutes of genuinely maximal intervals matched an hour of steady exercise on the aerobic measure and beat it on the anaerobic one. The catch is the intensity: 170% of VO2max is harder than most people have ever pushed on purpose, which is why the protocol is short.
This timer: 20/10 × 8, fixed
The work, rest and rounds are fixed at 20 seconds, 10 seconds and 8, the published protocol, so there is nothing to set: press Start. A 10-second get-ready counts down first, then WORK in red and REST in green alternate, with Round 3 / 8 under the digits, three beeps at 3-2-1 before every change and a longer tone on the change. The alarm rings when the eighth work period ends; the rounds add up to 3:50, 4:00 with the get-ready.
You can add a warm-up and a cool-down in seconds, since the original study used a 10-minute warm-up, and change the get-ready length. For different work or rest times, or more rounds, use the interval timer, which has the same engine and sounds with every number editable.
How to do a Tabata session
Warm up for 5–10 minutes until you are sweating lightly; starting a maximal effort cold is the usual way to pull something. Pick one movement you can do hard and safely for 20 seconds without technique falling apart: cycling or rowing against resistance, burpees, squat jumps, mountain climbers, kettlebell swings, sprints. The study used a cycle ergometer, which is still the easiest way to reach the intended intensity.
In each 20 seconds go as hard as you can from the first second, not building up; use the 10 seconds to breathe, not to walk away. If you can hold a conversation or the eighth round feels like the first, it was not a Tabata. Finish with 3–5 minutes of easy movement.
Common mistakes
Doing it every day: the study ran four Tabata sessions a week plus one steady session, and recovery is where the adaptation happens. Stacking rounds: "two Tabatas" at true intensity is rarely possible, and if it is, the first was not maximal. Using it as a beginner's first workout: the protocol assumes a trained base; start with 30/30 or 20/40 intervals on the interval timer and work up.
Choosing a movement that limits you by skill rather than effort: complex lifts under fatigue are an injury risk, so keep the movement simple. And treating the four minutes as a fat-loss trick: it is a conditioning tool, and the calorie total of four minutes is small whatever the intensity.
Beeps, tone and the alarm
Three short beeps mark the last 3, 2, 1 seconds of each period and a higher tone marks the change, so you never have to look at the screen mid-burpee; the get-ready ends with the same tone as your GO. After the eighth round the alarm you chose repeats until you stop it. Sounds are made in the browser and pre-scheduled on its audio clock, so they land on the second even if the page is busy; switch the 3-2-1 beeps off or pick None in the alarm settings if you train in a shared space.
On a phone: screen, background and iPhone
Keep screen on is on by default on phones, so the four minutes are not cut by auto-lock, and F gives a full-screen view with the colour, seconds and round large enough to read from the floor. Each period's end time is fixed when it starts, so the timer is exactly on schedule after any glance away. On an iPhone keep the tab in front, since Safari pauses hidden pages; iOS 17+ plays the beeps through the silent switch, and Android phones vibrate at the end.
Other numbers and other timers
For 30/15, 40/20, 45/15, EMOM or boxing rounds, or any custom work, rest and round count, open the interval timer or the HIIT timer, which start from editable presets. The stopwatch times a run or a set with laps, and the plain timer counts one length for a plank or a rest between sets. They share this page's sounds and settings.