Interval timer

Set work and rest lengths, the number of rounds, and optionally sets, a warm-up and a cool-down. The timer counts every round and chimes at each change, so you can keep your eyes off the screen.

Round 1 of 5

0:45

Step 1 of 9 · Next: Rest · 4 min 45 s in total

Chime at each change

Full schedule (9 steps, 4 min 45 s)

#	Step	Starts at	Length
1	Round 1 of 5	0:00	0:45
2	Rest	0:45	0:15
3	Round 2 of 5	1:00	0:45
4	Rest	1:45	0:15
5	Round 3 of 5	2:00	0:45
6	Rest	2:45	0:15
7	Round 4 of 5	3:00	0:45
8	Rest	3:45	0:15
9	Round 5 of 5	4:00	0:45

How to use the interval timer

Start from a preset or type your own numbers. All lengths are in seconds; editing any field switches the preset to Custom.
Rounds is how many work intervals make one set. Sets repeats the whole block, with the longer rest between sets. Leave sets at 1 for a single block.
Warm-up and cool-down are optional; set them to 0 to leave them out.
Press Start. A chime marks each change. The panel turns green during rest, and the schedule table highlights where you are.

How the rounds are laid out

The timer builds the session in a fixed order: warm-up, then for each set its rounds of work, each followed by rest, then the cool-down. Two rules keep the session honest:

The last round of a set is followed by the rest between sets, not the normal rest.
The last round of the last set goes straight into the cool-down, with no rest in between.

So the total length is warm-up + cool-down + sets × rounds × work + sets × (rounds − 1) × rest + (sets − 1) × rest between sets. The schedule under the timer lists every step with the time it starts.

Worked example

The "40 s on, 20 s off × 8" preset has a 2-minute warm-up and a 2-minute cool-down. Eight rounds of 40 seconds is 5 minutes 20 seconds of work. There are seven rests of 20 seconds between them, 2 minutes 20 seconds, because the eighth round goes straight into the cool-down. Adding the warm-up and cool-down gives 11 minutes 40 seconds. Changing it to 2 sets with a 60-second rest between sets gives 16 rounds of work (10 minutes 40 seconds), 14 short rests (4 minutes 40 seconds), one set rest (1 minute) and the same 4 minutes of warm-up and cool-down: 20 minutes 20 seconds.

The presets

Preset	Work : rest (s)	Work time	Total with warm-up and cool-down
Desk movement snack: 45 s on, 15 s off × 5	45:15	3 min 45 s	4 min 45 s
30 s on, 30 s off × 10	30:30	5 min	13 min 30 s
40 s on, 20 s off × 8	40:20	5 min 20 s	11 min 40 s
20 s on, 10 s off × 8 ("Tabata" format)	20:10	2 min 40 s	11 min 50 s
Every minute on the minute × 10	—	10 min	10 min

Desk movement snack

Five rounds of 45 seconds, with 15 seconds between them to switch: five minutes in all, the default on this page. It suits a break from sitting, done at an easy, comfortable effort. Ideas for the work rounds: march on the spot, sit-to-stand from your chair, wall push-ups, calf raises holding the desk, and slow arm circles. Choose movements you can do safely in the space you have.

30 / 30 and 40 / 20

General-purpose formats for a short circuit. Equal work and rest (30 / 30) is the gentler of the two; 40 / 20 gives twice as much work as rest.

20 / 10 × 8

Four minutes of intervals, the timing known as Tabata. The name comes from a 1996 study by Izumi Tabata's group, in which trained athletes rode exercise bikes at an intensity well above what most people would reach in a class. Using the timing does not reproduce the study; it is simply a short, demanding format. It includes a longer warm-up here for that reason.

EMOM

Every minute on the minute, ten times. The work is whatever you set yourself to do at the start of each minute; the rest of the minute is recovery. The timer simply chimes each minute.

Limits

The timer keeps time; it does not know what you are doing or how hard. It will not tell you whether a workout suits you, and it does not track heart rate or count repetitions. It runs in this browser tab and stops if the tab is closed or the device sleeps; on a phone, keep the screen on while using it. Nothing is saved between visits.

For breaks that are about loosening up rather than effort, the stretch break timer and the desk stretch routine are a better fit.

Common questions

What is an interval timer for?

Anything that alternates between a period of effort and a period of rest: a short movement break at your desk, a bodyweight circuit, skipping, stretching held for set times, or practising a skill in short bursts. It keeps count of the rounds so you do not have to.

What does 20 seconds on, 10 seconds off mean?

Twenty seconds of work followed by ten seconds of rest, repeated, usually eight times for four minutes. The format is often called Tabata after a 1996 study led by Izumi Tabata. That study used trained athletes working at a very high intensity on exercise bikes; most workouts called Tabata today borrow the timing, not the intensity.

Why is there no rest after the last round?

Because the cool-down follows straight away, and a rest immediately before a cool-down is just a longer cool-down. Between sets, the longer "rest between sets" replaces the last short rest of the set for the same reason.

What is EMOM?

Every minute on the minute: at the start of each minute you do a set amount of work, and whatever is left of the minute is your rest. On this timer, set work to 60 seconds and rest to 0; the chime at each round marks the top of the minute.

Is interval training safe for me?

That depends on you and on how hard you work, which this page cannot know. Short movement breaks at an easy effort are suitable for most people. For higher-intensity intervals, build up gradually, and if you have a heart condition, are pregnant, are returning from injury or have not exercised for a long time, check with a doctor first.