How is the session total calculated?
Total seconds = warm-up + rounds × (work + rest) + cooldown. Rest is omitted when it is zero; positive rest is included in every round, including the final round.
Workout setup
Set Your Intervals
Workout setup
40s work · 20s rest · 8 rounds
10:00 total
Interval workout
Ready
8 rounds
Next: Ready
01:00
Settle in, check your space, then start.
Phase 0%Workout 0%
Space: start/pause · R: reset · Settings lock after start
HIIT Timer for Custom Work and Rest Intervals
Build an interval session with editable work, recovery, warm-up, and cooldown periods, then track the active phase and round in one view.
Set the phases and check the session total
Choose a preset or enter work, rest, rounds, warm-up and cooldown values. Each round contains one work period and a rest period when rest is above zero, including after the final work period. Warm-up and cooldown sit outside the rounds. For example, two rounds of 20 seconds work and 10 seconds rest, plus 10 seconds warm-up and 10 seconds cooldown, total 80 seconds.
Start, pause and review transitions
Start Workout begins the configured phases and locks settings. Pause stops the current countdown; Resume continues it, Skip advances one phase, and Reset returns to the setup. Sound can be disabled while the phase label and progress remain visible. The configured intervals are a timing plan, not a recommendation for an exercise intensity or a personal health outcome.
Once you have found a repeatable work-to-recovery pattern, compare the pacing and session structure with the free online HIIT timer from IntervalTimers.org.
HIIT Timer FAQ
Does this online HIIT timer keep time in a background tab?
The code compares a stored phase end time with the current clock and carries lateness into later phases. Background throttling or device suspension can still delay updates and sound. Real sleep and power-saving behavior must be checked on the target device.
What does the Tabata HIIT timer preset include?
It schedules eight rounds of 20 seconds of work and 10 seconds of recovery. Warm up separately, choose suitable movements, and avoid treating a preset as individualized medical or coaching advice.
Can I use the interval timer without sound?
Yes. Turn sound off in the setup card. The phase color, large countdown, round counter, and progress bar continue to provide clear visual transitions.
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