What is a HIIT interval timer?

A HIIT (high-intensity interval training) timer alternates short, hard work bouts with timed rest periods. You set the work seconds, rest seconds, number of rounds and number of sets, and the timer runs the whole sequence automatically with a clear countdown and audio cues so you never have to watch a clock mid-workout.

How do I set up a Tabata workout?

Tabata is 20 seconds of work and 10 seconds of rest repeated for 8 rounds — four minutes total. Use the built-in Tabata preset, or set work to 20, rest to 10, rounds to 8 and sets to 1. Add a 10-second prepare phase so you have time to get into position before the first bout.

What is the difference between rounds and sets?

A round is one work-then-rest cycle. A set is a group of rounds. After the last round of a set the timer can insert a longer set break before the next set begins. Use sets when you want to repeat a circuit several times with a proper recovery in between, such as three sets of six 30-second exercises.

Will the timer keep my screen awake?

On browsers that support the Screen Wake Lock API the timer requests a lock while it is running, so your phone or tablet screen stays on through the workout. If the browser does not support it the timer still runs normally; just disable auto-lock in your device settings as a fallback.

Can I run EMOM workouts with this timer?

Yes. EMOM (every minute on the minute) is just a 60-second work bout with no rest, repeated for the number of minutes you want. Load the EMOM preset or set work to 60, rest to 0 and rounds to the minute count. You will hear a beep at the top of every minute.

Is anything sent to a server?

No. The timer, the audio beeps and your saved routine all run entirely in your browser. Your routine is stored in your browser's local storage, and the export and import buttons move it as a plain JSON file on your own device. Nothing is uploaded.

HIIT Interval Timer — Gera Tools

A configurable HIIT interval timer for circuit training, Tabata, EMOM and boxing-style rounds. Build a routine from four simple numbers — work seconds, rest seconds, rounds per set and number of sets — then hit start and follow a big countdown that beeps on every transition and tracks exactly which round and set you are on. It is built for anyone doing timed interval work who is tired of squinting at a stopwatch or counting reps in their head: home workouts, gym circuits, kettlebell complexes, stretching sequences, even study sprints.

How it works

You describe your session as a sequence of phases. An optional prepare countdown gives you time to get into position. Then each round runs a work phase followed by a rest phase; the rest is skipped after the final round of a set. When you train more than one set, a longer set break is inserted between them. The tool expands all of that into an ordered list of timed segments and walks through them one by one.

The countdown is wall-clock based, so it stays accurate even if the browser throttles background timers — it measures real elapsed time on every tick rather than assuming a perfect interval. Each phase change plays a distinct tone (a high beep for work, a softer one for rest, a low one for set breaks), and an optional 3-2-1 count-in ticks during the last three seconds of every phase so you can brace for the switch without looking. A coloured ring shows progress through the current phase, a bar shows progress through the whole session, and a clickable timeline lets you jump straight to any phase. You can pause, resume, skip forward or back, and reset at any time.

Example

Say you want three sets of six 30-second exercises with 15 seconds rest between exercises and a full minute of recovery between sets. Set work to 30, rest to 15, rounds to 6, sets to 3 and set break to 60. The timer builds 33 phases — a prepare countdown, eighteen 30-second work bouts, fifteen 15-second rests and two 60-second set breaks — for a total session of just over 18 minutes. As you train, the header reads Round 4/6 · Set 2/3 so you always know your place.

Workout	Work	Rest	Rounds	Sets	Total
Tabata	20s	10s	8	1	4:00
Classic HIIT	40s	20s	10	1	10:00
EMOM	60s	0s	10	1	10:00
Pyramid circuit	30s	15s	6	3	18:00+

Your routine is saved automatically in this browser, and the export button writes it to a JSON file you can keep or share — everything happens on your device, with nothing uploaded.