HIIT Interval Timer
Set your rounds, work time and rest time, then press start. The timer uses exact clock timestamps, so it stays accurate even when you switch browser tabs.
Get ready
00:00
Round
—
Elapsed
00:00
Remaining
—
Tip: keep this tab open and the volume up so you can hear the beeps when each phase changes.
How to use
- Enter the number of rounds and the work and rest seconds (you can change them before starting).
- Press Start. A 5 second prepare phase counts down first so you can get into position.
- Press Pause any time to freeze the timer and Reset to clear it.
FAQs
Yes. The timer compares the real clock time against each phase end time instead of counting ticks, so background throttling cannot drift it off track.
Most phones and browsers block audio until you press a button first. Pressing Start unlocks the sound, and the volume must be up with silent mode off.
No. The whole timer runs in your browser with local JavaScript and nothing leaves your device.
Frequently Asked Questions (FAQ)
How do I set up a HIIT workout on this timer?
Enter the number of rounds and the work and rest seconds before starting. When you press Start, a 5 second prepare phase counts down first so you can get into position.
Does the timer stay accurate if I switch tabs?
Yes. The timer compares the real clock time against each phase end time instead of counting ticks, so background throttling cannot drift it off track.
Why is there no sound on my phone?
Most phones and browsers block audio until you press a button first. Pressing Start unlocks the sound, and your volume must be up with silent mode off.
Is my data sent anywhere?
No. The whole timer runs in your browser with local JavaScript and nothing leaves your device.