Interval Timer (HIIT)

How to use the interval timer

This tool is built for the pattern that most interval training uses: a short prep countdown, then alternating work and rest blocks for a set number of rounds. Pick a preset or enter your own times. A Tabata round is 20 seconds of work and 10 seconds of rest, repeated eight times; a typical HIIT round is 30 to 45 seconds of work and 15 to 30 seconds of rest.

Hit Start and put your phone face-down or prop it within earshot. The timer beeps three short cues at 3 · 2 · 1 before every phase change and a single long cue when the new phase begins, so you can keep moving without looking at the screen. You can pause any time with the red button and resume from the exact remaining time on the current phase — the countdown stays accurate even if you background the tab, because remaining time is calculated from a target timestamp rather than by counting ticks.

Setting Rest to zero turns the timer into an EMOM-style clock (every minute on the minute, or every N seconds if you shorten the work block) — consecutive work rounds without rest. Setting Prep to zero skips the lead-in. The total-workout readout below the settings updates live so you can confirm the session length before you start. For sound to play you must tap the Sound on button once; browsers block audio until a page receives a user gesture, and a single tap is enough to unlock it for the whole session.