Can I use this for Tabata?

Yes. For classic Tabata, set work to 20 seconds, rest to 10 seconds, and 8 rounds. Adjust freely for any HIIT or circuit protocol.

Do the beeps need an internet connection?

No. The transition beeps are generated in your browser with the Web Audio API, so they work offline and nothing is downloaded or uploaded.

What happens if I set rest to zero?

The timer moves straight from one work interval to the next with no rest phase, which is useful for continuous circuits.

How long is a classic Tabata workout?

A single Tabata block is 8 rounds of 20 seconds work and 10 seconds rest, which totals 4 minutes (8 × 30 seconds). Add a prepare phase at the start to get ready before the first work interval.

What is the prepare phase for?

Prepare is a short countdown before the first work interval so you can get into position. Set it to 5-10 seconds, or to 0 to start working immediately.

Will the timer keep running if my screen locks?

Browsers may pause timers or audio when a tab is in the background or the screen sleeps, so keep the tab active and your device awake during a workout for reliable cues.

Interval Timer (HIIT)

Interval timer for HIIT, Tabata and circuits

A work/rest interval timer for HIIT, Tabata and circuit training. Set your phases once and follow the audio cues, so you can focus on the exercise instead of watching a clock or counting reps in your head.

How it works

You define four values: prepare (a get-ready countdown), work (the active interval), rest (recovery between intervals) and the number of rounds. When you press Start, the timer counts down the prepare phase, then alternates work → rest for each round, showing the current phase and round number. At every phase change it plays a beep generated with the Web Audio API, so the cue works offline with no audio file to download. Setting rest to 0 chains work intervals back to back.

Example

A classic Tabata block:

Phase	Duration	Repeats
Prepare	10 s	once
Work	20 s	8 rounds
Rest	10 s	between rounds

Total active time is 8 × (20 + 10) = 240 seconds (4 minutes) after the 10-second prepare.

Everything runs in your browser — the audio cues are generated locally, so the timer works offline and nothing about your workout is ever uploaded.