Interval Timer

An interval timer runs a workout made of rounds: a stretch of hard work, then a stretch of rest, repeated. You set the work and rest in seconds, the number of rounds, and how long you want to get ready before the first one. Then press Start and follow the screen — or just the sound.

The display shows what you should be doing — Get ready, Work, Rest or Done — with a large countdown for the current stretch and the round you are on. The bar beneath it is the whole workout, with the time gone and the time left.

The beeps tell you everything without looking. Three short ticks count down the last three seconds of every stretch. A long high beep means work; a long low beep means rest. Three high beeps mean the workout is over. The beeps are queued a few seconds ahead on the audio hardware's own clock, so a busy phone cannot make one late.

Tabata is 20 seconds of all-out work and 10 seconds of rest, eight times. With the 10-second get-ready it takes 4:00 exactly; the work and rest alone are 3:50, because there is no rest after the last round. 30/30 is ten rounds of equal work and rest, 9:40 in all. 40/20 is eight rounds of 40 seconds on and 20 off, 7:50 in all. EMOM — every minute on the minute — runs ten one-minute rounds back to back with no rest stretch: you finish the set and rest for whatever is left of the minute. It takes 10:10 with the get-ready.

To make your own workout, type the numbers. Work can be 5 seconds to 10 minutes, rest 0 to 10 minutes, and up to 99 rounds. Set rest to 0 to run rounds back to back. While a workout is running or paused its settings are locked; press Reset to change them.

Pause stops the clock where it is and Resume carries on from the same second, without replaying any beep you already heard. The address bar always describes the workout on screen — #preset=tabata for a preset, every number for anything else — so you can bookmark it or send it to a training partner. Whether the sound is on is remembered on this device and is not part of the link.

Everything runs in your browser. There is no account and nothing is sent anywhere, and the page works offline once it has loaded. It does not keep your screen awake, so set your phone's screen timeout long enough for the workout, or leave the page in front.

Link to this tool with values filled in

Everything after the # stays in your browser — it is never sent to a server — so a link like this opens the tool ready to go without the values travelling anywhere but the address bar:

https://crunchify.net/tools/interval-timer#preset=tabata

Join the settings with &, and percent-encode each value so that spaces, newlines and any #, &, = or % inside one do not break the link. Leave a setting out to accept its default. If a setting is not recognised, the page says so rather than quietly ignoring it.

• preset (also workout or pattern) — tabata, 30-30, 40-20 or emom. A named workout: `tabata` (20s work, 10s rest, 8 rounds), `30-30` (30s work, 30s rest, 10 rounds), `40-20` (40s work, 20s rest, 8 rounds), `emom` (60s work, 0s rest, 10 rounds). Tabata when omitted.
• work (also on or high) — a whole number from 5 to 600. Seconds of work per round, 5–600. Replaces the preset's.
• rest (also off or low) — a whole number from 0 to 600. Seconds of rest between rounds, 0–600; 0 runs the rounds back to back. Replaces the preset's.
• rounds (also sets or reps) — a whole number from 1 to 99. How many rounds, 1–99. Replaces the preset's.
• prep (also warmup or countdown) — a whole number from 0 to 60. Seconds to get ready before the first round, 0–60. Replaces the preset's.