Interval Timer
Work / rest rounds for HIIT and Tabata — with beeps and a screen that stays awake.
An interval timer for HIIT, Tabata, circuits, EMOM sets, boxing rounds and stretching routines — anywhere work and rest alternate on a clock. The display counts with timestamps rather than naive ticks, so a long session does not drift.
Related tools: Online Metronome
How to use
- Set work seconds, rest seconds and rounds — the classic Tabata preset (20 / 10 / 8) is loaded for you.
- Press Start. A get-ready countdown runs first (set it to None if you hate waiting), then beeps mark every phase change: two sharp beeps for work, one low beep for rest.
- The timer asks your device to keep the screen awake while it runs, and the display is readable across a room. Pause any time; Reset returns to your settings.
About this tool
It is deliberately distinct from the Pomodoro timer on this site: that one is built for desk focus cycles with breaks; this one is built for physical rounds — louder beeps, a glanceable display, no screen sleep mid-set.
Everything runs in your browser. No account, no workout data recorded anywhere.
How it works
Interval training alternates high-effort work bouts with recovery on a fixed clock. The dose is the ratio and the count: work seconds × rounds, with rest deciding how repeatable the effort is. The famous Tabata protocol — 20 seconds maximal work, 10 seconds rest, 8 rounds — improved both aerobic and anaerobic capacity in Dr. Izumi Tabata’s 1996 study, in just 4 minutes of work.
The timer itself is built not to drift: every phase is computed from timestamps (start time + planned duration) rather than by counting screen ticks, so a distracted phone cannot stretch your rest by a few seconds per round — the difference between a hard session and an impossible one at round 7.
Worked examples
True Tabata finisher: Work 20 s, rest 10 s, 8 rounds, no get-ready countdown once you know the drill. Pick one movement — squats, kettlebell swings, bike sprints — and keep the work genuinely maximal; the protocol fails politely if you pace it.
Boxing rounds: Work 180 s, rest 60 s, 12 rounds, 10 s get-ready. The single low rest-beep and double work-beep tell you where you are without looking at the screen — exactly what the beep pattern is designed for.
Quick reference
| Protocol | Work | Rest | Rounds |
|---|---|---|---|
| Tabata | 20 s | 10 s | 8 |
| EMOM (every minute) | within the minute | remainder | 10–30 |
| Boxing / MMA rounds | 180 s | 60 s | 3–12 |
| Gentle circuits | 30 s | 30 s | 6–10 |
| Stretching routine | 30 s per pose | 10 s to switch | as needed |
Frequently asked questions
What is Tabata, exactly?
A 4-minute protocol studied by Dr. Izumi Tabata: 8 rounds of 20 seconds all-out work with 10 seconds rest. It is the default preset here — and “all-out” is the honest part; if you can chat during round 7, it was not Tabata, it was intervals (which are also fine).
How is this different from the Pomodoro timer?
Purpose and environment. Pomodoro alternates 25-minute desk-focus blocks with breaks. This timer alternates seconds-to-minutes physical rounds, beeps loud enough for a gym corner, keeps the screen awake, and shows one huge countdown. Same family, different jobs.
Why did my screen still go dark?
The timer requests a Wake Lock and most modern browsers honour it while the tab is visible — but a low-battery mode, switching apps, or an older browser can override it. Keeping the tab in front during the workout avoids nearly all cases.
Can I run it with no rest between rounds?
Yes — set Rest to 0. The rounds then run back-to-back with just the phase beep between them, which suits EMOM and circuit formats.
Does it work with the phone in my pocket?
The beeps keep coming while the tab is open in the foreground app; if the browser is fully closed or the phone hard-sleeps the page, timing stops. For pocket use, keep the browser open and the volume up.
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