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00:40
Work
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Customise your work and rest durations, set your round count, and start instantly. Includes Tabata (20/10), HIIT 40/20, 30/30, and custom presets. The ring turns red during work and green during rest. No ads, no accounts.
High-Intensity Interval Training protocols like 40/20 and 30/30 are proven to improve VO2 max and burn fat in minimal time.
Standard boxing rounds are 3 minutes work, 1 minute rest. Set custom durations for sparring, bag work, and conditioning drills.
Box breathing (4/4/4/4), Wim Hof cycles, and alternate nostril breathing all use timed intervals — this timer handles them all.
Tabata science: The original 1996 study by Izumi Tabata found that 20 seconds of maximum-intensity work with 10 seconds rest, repeated 8 times, produced VO2 max improvements of 14.5% in 6 weeks — significantly greater than moderate-intensity steady-state exercise. The protocol is only 4 minutes but must be performed at genuine maximum effort to achieve these results.
Pre-programmed into the presets above. Select any to auto-fill the inputs.
20 sec maximum effort, 10 sec rest, 8 rounds. Total: 4 minutes. Most studied HIIT protocol. Requires true all-out intensity.
40 sec work, 20 sec rest, 8 rounds. Total: 8 minutes. More sustainable than Tabata — good for beginners and intermediate athletes.
30 sec work, 30 sec rest, 10 rounds. Total: 10 minutes. Equal work-rest ratio. Classic format for running intervals and rowing.
45 sec work, 15 sec rest, 6 rounds. Total: 6 minutes. 3:1 work-rest ratio. Challenging — builds both aerobic and anaerobic capacity.
An interval timer alternates between two timed phases — a work period and a rest period. It is the standard tool for Tabata (20/10), HIIT (40/20), boxing rounds (3 min/1 min), and any exercise using timed work-rest cycles. This timer includes Tabata, HIIT 40/20, 30/30, and 45/15 presets.
Tabata is a specific interval protocol: 20 seconds maximum effort, 10 seconds rest, 8 rounds, 4 minutes total. Developed by Dr Izumi Tabata in 1996, it produced 14.5% VO2 max improvement in 6 weeks — greater than moderate steady-state exercise. True Tabata requires near-maximal intensity.
Common evidence-based ratios: 1:1 (30 sec / 30 sec) for moderate intensity; 2:1 (40 sec / 20 sec) for intermediate; 4:1 (40 sec / 10 sec, Tabata) for high intensity. Beginners should start at 1:2 or 1:3 — more rest than work — and increase work density progressively over weeks.
Yes. Research consistently shows 15–25 minutes of genuine HIIT produces cardiovascular benefits comparable to 45–60 minutes of moderate steady-state cardio. The key is true high intensity during work periods — most people underestimate how hard the work intervals should feel.
Absolutely. This timer works for language learning drills, music practice, productivity sprints, speech rehearsal, classroom activity rotations, breathwork cycles, and cooking multiple dishes with overlapping timing.
For 20-second intervals (Tabata): 8 rounds. For 30–40 second intervals: 6–10 rounds. For 60-second intervals: 4–6 rounds. Total work time of 4–20 minutes is typical. More than 3 HIIT sessions per week without adequate recovery can impair adaptation.
HIIT alternates maximum-effort work with passive rest — you push as hard as possible during work periods. Circuit training rotates through different exercises with minimal rest — moderate intensity, sustained heart rate elevation. Both use interval timers but target different physiological adaptations.
No download, no account, no subscription. Open the browser, start training.
This interval timer was designed by fitness enthusiasts who were frustrated with ad-heavy apps that interrupt workout flow and require accounts just to set a 20/10 timer. Every preset — Tabata, HIIT 40/20, 30/30, 45/15 — is pre-wired with the exact work and rest durations used in published exercise science research. The ring colour changes automatically: red during work, green during rest, so you never need to look at a screen mid-exercise.
Sprint for 20 seconds, walk for 10. The visual ring and audio beep mean you can keep your eyes off the screen entirely during your sprint.
Set 60–90 second rest periods between sets. The audio alarm tells you when to lift again without checking your phone.
4-count inhale, 4-count hold, 4-count exhale, 4-count hold — use 4/4 intervals for box breathing or set custom phases for pranayama.