Interval Timer (Tabata)
This interval timer alternates work and rest periods for as many rounds as you set, with a sound at every change so you don't have to watch the screen. Tabata timing — twenty seconds of work, ten seconds of rest, eight rounds — is one of the presets.
Work, rest, repeat
An interval workout isn't one length of time — it's a pattern: work, rest, and the pair repeated for a set number of rounds. Set the work length, the rest length and how many rounds you want, and the timer runs the whole thing on its own from there. You can add a short count to get into position, a warm-up, a cool-down, and extra sets with a longer rest in between.
The screen shows which phase you're in, the time left in it and the round you're on, big enough to read from across a gym or a living room floor. A sound marks the start of every work period and every rest period, so you can keep your eyes on the exercise instead of the clock — work and rest each get a different sound, and three short beeps count you into every change.
Tabata, HIIT and rounds that match how gyms actually train
Tabata timing — twenty seconds of work, ten seconds of rest, eight rounds, four minutes total — is the preset most people here are actually looking for. It's named after the Japanese researcher Izumi Tabata, whose 1990s study of short, very hard intervals popularized the pattern, and it shows up in CrossFit boxes and HIIT classes in gyms around the country, not just in a browser tab.
Other presets cover longer HIIT blocks (thirty to sixty seconds of work with a similar or shorter rest), EMOM rounds, and boxing, where a professional round is three minutes with a minute of rest between rounds — training and amateur rounds are often shorter. Same timer, different numbers; set the lengths once and it repeats for as long as the workout needs.
Runs off your device clock, keeps nothing
Every phase change is worked out from your device's clock instead of counted down tick by tick, so a round still ends on time even after a moment in a background tab. The sounds for the next few minutes are queued up in advance for the same reason, and the screen stays on for the whole workout wherever your browser allows it. The one thing that can still cut a sound short is a phone that locks its screen or a browser saving power — keep the page in front during a workout, or turn on the end-of-workout notification instead.
Nothing about the workout gets uploaded. The lengths you set stick around in your own browser for next time, workouts you save by name stay there too, and there's no account and nothing to install — it's free, same as every timer on this site.
Questions and answers
What is an interval timer?
A timer that switches between a work period and a rest period for a set number of rounds, with a sound at every change. It's used for interval training, circuits and Tabata-style workouts.
What is Tabata timing?
Twenty seconds of work and ten seconds of rest, repeated eight times, for four minutes total. It's the preset built specifically for that pattern here.
Can I set my own work and rest times?
Yes. Work, rest and the number of rounds are each set separately, so something like forty seconds on and twenty off for ten rounds takes a few seconds to enter.
Tumatakbo pa rin ba ito kung nasa ibang tab ako?
Yes. Every change is worked out from your device's clock instead of counted down tick by tick, so a background tab doesn't make a round run late.
Can I save my own workouts?
Yes. Name the current workout and save it, and it stays in this browser, ready to load again next time. Nothing is uploaded, and there's no account.
Is the interval timer free?
Yes. It runs in your browser with no account, no sign-up and nothing to install.