A configurable interval timer for any high-intensity workout. Set your work and rest durations, choose your rounds, and hit Start. Audio cues fire at every transition so you can focus on the movement instead of the clock. Save your favourite setups and reload them in one tap.
High-intensity interval training is a structured approach to cardiovascular exercise built around alternating bursts of intense effort and recovery. The defining characteristic is that the work periods are genuinely hard — not a brisk jog, but near-maximum output. Sprint, drive, push. Then rest. Repeat.
Tabata is the most well-known HIIT protocol: 20 seconds of maximal effort followed by 10 seconds of rest, repeated 8 times for exactly 4 minutes. It was developed by Dr. Izumi Tabata in 1996 through research at the National Institute of Fitness and Sports in Tokyo, where it was shown to improve both aerobic and anaerobic capacity simultaneously. EMOM (every minute on the minute) is a popular variant from CrossFit: begin a fixed set of reps at the top of each minute, then rest for whatever time remains before the next minute starts.
The appeal of HIIT is efficiency. A well-structured 20-minute session — including rest periods — can produce cardiovascular and metabolic adaptations comparable to much longer steady-state cardio. The tradeoff is that genuine high-intensity intervals are taxing on the nervous system, joints, and connective tissue. Most people shouldn't exceed 2–3 HIIT sessions per week. If you can do it every day, the intervals probably aren't hard enough.
Set your work time, rest time, number of rounds, and the prep countdown (a brief window before the first work interval begins — use it to get into position). Tap a preset chip to fill the inputs automatically for common formats, or dial in your own numbers for a custom session.
Hit Start. The timer runs automatically through every round, switching phases and firing audio cues at each transition. You don't need to watch the screen — the beeps tell you when to go and when to stop. When all rounds are done, the completion screen shows your total time and total work duration.
To save a configuration you use regularly, tap "Save Workout", enter a name, and hit Save. Saved workouts appear below the inputs and can be loaded or deleted at any time. Settings are stored in your browser's local storage — no account required.