Quick answer: enter work time, rest time and the number of reps, plus warm-up and cool-down, then press Start. The default session (10:00 warm-up, 8 x 2:00 hard with 1:00 rest, 10:00 cool-down) lasts 43:00.
How to use the running interval timer
Type times as m:ss, or tap a preset to fill in work, rest and reps. Warm-up and cool-down are timed as easy running or walking; set them to 0:00 if you warm up on your own. During the session the screen shows the current step, the time left in it, what comes next and the time left in the whole workout. Three short beeps count down the end of each step, and you can skip a step if you need to.
Timing reps instead of measuring them
A timer is ideal off the track, where you cannot see 400 m marks. Take a rep time from your training paces: on the training pace calculator, a 25:00 5K runner's interval pace works out to 1:54 per 400 m, so the "8 x 1:54" preset gives roughly the effort of 8 x 400 m on a track. Run by effort on hills and in wind; the time stays fixed while the distance changes.
Worked example
The "20s / 10s x 8" preset runs 8 work periods of 20 seconds with 10-second rests between them: 160 seconds of work and 70 of rest, 3:50 in all, before any warm-up and cool-down. The final rest is left out when a cool-down follows, so the last hard rep flows straight into the easy running.
Choosing work and rest
Short, very hard reps need long rests relative to the work; longer reps at threshold effort need only short breaks. The presets cover a few common shapes: equal work and rest (1 minute on, 1 minute off), longer reps with shorter recovery (5 x 3:00 with 2:00 jog) and the 20-on, 10-off pattern often called Tabata style. Match the hard pace to your fitness with the training pace calculator rather than guessing.
Using it on a phone
Keep the page open and the screen on during the session; browsers may pause timers in the background, and the timer catches up when you return. Voice cues work through headphones on most phones.
For easy runs with walk breaks, use the run walk timer. On a track, pair it with the track pace chart. For HIIT and circuit workouts that are not running, try the HIIT and circuit interval timer.
Formula and examples checked . Found a problem? Tell us.
Questions
What is a good interval workout for running?
One simple shape is 6 to 8 hard reps of 1 to 3 minutes with equal or shorter easy recoveries, like the presets above. Set the hard pace from a recent race with the training pace calculator.
How do I time intervals without a track?
Use time instead of distance: run each rep for a set time at your interval effort, then recover for a set time. This timer counts both for you.
Can I use this as a Tabata timer?
Yes. The 20s / 10s x 8 preset sets 20 seconds of work and 10 seconds of rest for 8 rounds.
Does the running interval timer work in the background?
Keep the screen on for reliable beeps. If the browser pauses it, the timer catches up on the steps that passed when you return.