Interval Timer (HIIT & Tabata)
Free interval timer for HIIT, Tabata and circuit training with work and rest rounds, multiple sets and audio cues that run in your browser.
π Runs entirely in your browser β nothing is uploadedHow the interval timer works
An interval timer alternates between hard effort and recovery so you can train by the clock instead of counting in your head. Set a get-ready countdown, the length of each work period, the length of each rest period, how many rounds make up a set, and how many sets you want. The timer then runs the whole session automatically, switching phase with a clear colour change and a beep so you never have to look at the screen mid-exercise.
The three presets cover the most popular formats. Tabata is the classic 20 seconds of all-out work followed by 10 seconds of rest, repeated for eight rounds, which makes a four-minute workout. A 30/30 HIIT block suits beginners who need longer recovery. The circuit preset adds three sets of six rounds with a full minute of rest between sets, a good structure for strength circuits, boxing rounds or swimming drills.
Accurate, private and distraction-free
Every phase is computed from real timestamps rather than by counting interval ticks, so the timer stays accurate even if your browser throttles background tabs or the phone screen dims. The last three seconds of each phase tick audibly, and a longer, higher tone marks the start of each work period. You can turn sound off if you train with headphones and prefer to watch the display.
The remaining time for the whole workout is always shown under the clock, so you know exactly how much is left. Pause freezes the current phase and Resume continues from the same second. Everything runs locally in your browser; nothing is uploaded and no account is needed. Keep the tab open and the screen awake during your session for the best results.
Tips for better interval training
Pick a work length you can sustain at high intensity for every round; if your form collapses in round five, shorten the work period or lengthen the rest. Warm up first, since the get-ready phase is only a countdown. For skill sessions such as boxing or sparring, try 3-minute rounds with 1 minute of rest, and use the sets field to add more blocks.
How to use
- Set the intervalsEnter the get-ready time, work seconds, rest seconds, rounds per set, number of sets and the rest between sets, or tap a preset.
- Start the workoutPress Start. The colour, label and beeps tell you whether it is time to work, rest or get ready.
- Pause or resetUse Pause to stop mid-session and Resume to continue, or Reset to return to the beginning.