Interval Timer
Work and rest in sequence — Tabata, HIIT, EMOM, circuits, stretching, Pomodoro. It keeps time from the clock rather than by counting ticks, so it stays accurate when the tab is in the background, and it beeps on time even while you are in another app.
Start from a preset
Or set it yourself
Press Space to start or pause, R to reset, S to skip. Your settings and a running session are kept on this device, so a reload or an accidental tab close does not lose your place.
Why the timing holds up
Most timers in a browser count seconds by adding up interval callbacks. Browsers throttle those callbacks to roughly one a minute once a tab is in the background, so a ten‑minute timer left behind a another tab finishes late — sometimes by minutes — and there is no warning that it happened.
This one never counts. It records the moment the session started and works out where you are from the current time whenever it draws, so a display that went stale while you were away is correct the instant you come back. The beeps are handled separately: every cue for the whole session is scheduled on the audio clock in advance, which browsers do not throttle, so they sound on time even while the tab is hidden.