Interval Timer
An interval timer alternates timed work and rest periods for a chosen number of rounds. Set both durations and the round count here; the page labels each phase and moves to the next one when its countdown ends.
Set up your timer
Ready
Work interval
Set your options, then start.
The countdown updates from your device clock when the page can run. Browser audio may be blocked in a background tab, and no alert is guaranteed while the device sleeps or the page is closed.
How to use this timer
- Enter the work interval and rest interval in seconds.
- Choose how many rounds to run, then select Start.
- Pause, resume, reset, or skip the current phase as needed.
Set work, rest, and rounds
The default is 45 seconds of work followed by 15 seconds of rest for eight rounds. Change the values to match your own plan. The final work round ends the sequence without adding an extra rest period.
Use the intervals you planned
This tool only keeps time; it does not recommend an exercise, pace, or work-rest ratio. You can use it for practice blocks, classroom activities, rehearsals, or any routine that needs repeated phases.
Background timing and sound
The display uses the device clock to catch up after browser throttling. Sound depends on browser permissions and device power state, and the sequence resets if you reload the page. Keep the device awake if you need to hear phase changes.
Common questions
Can work and rest lengths be different?
Yes. Enter each interval separately. The timer uses your values for every round.
Does the last round include a rest?
No. The sequence ends after the final work interval, so the displayed round count matches completed work intervals.
Can I pause between intervals?
Yes. Pause freezes the current phase, and Resume continues from the remaining time.