⏱️ Tabata Interval Timer
Set your work, rest, rounds and warm-up time to build a Tabata-style interval plan, then run a live countdown timer.
How the plan is assembled
Your four numbers expand into a list of phases: an optional warm-up, then work and rest alternating. Rest is skipped after the last round, so the session ends on effort:
total = warm-up + rounds × work + (rounds - 1) × rest
phases = 1 + rounds + (rounds - 1)The defaults - 10 s warm-up, 20 s work, 10 s rest, 8 rounds - build 16 phases totalling 240 seconds. That is the classic four-minute Tabata, and it lands on four minutes only because the warm-up replaces the trailing rest the timer drops. Set the warm-up to 0 and the session is 3:50.
Running it
- Start rebuilds the plan. Editing a box mid-session does nothing until you press Start again; Reset stops the clock and returns you to the summary.
- Rest of 0 makes it continuous. The rest phases vanish rather than appearing as zero-second entries, giving a block of back-to-back work.
- Limits are 600 seconds and 50 rounds per box - room for a 10-minute interval or a very long circuit.
Frequently asked questions
How long is a Tabata workout?
Four minutes of intervals: eight rounds of 20 seconds work and 10 seconds rest. This timer adds whatever warm-up you set on top.
What is the 20 10 Tabata protocol?
It comes from Izumi Tabata's 1996 study of speed skaters, who did eight 20-second efforts at a punishing intensity with 10 seconds between. The structure copies easily; the effort level was the point.
Will the timer keep running in a background tab?
Not reliably. Browsers slow down timers in hidden tabs to save battery, so the countdown can drift behind real time. Keep the page on screen for the session.