Interval Timer
Run customizable work/rest intervals with an independent, browser-side monotonic clock.
Play Interval Timer
Choose work and rest lengths and rounds, then start the alternating interval timer.
How to play Interval Timer
Choose work and rest lengths and rounds, then start the alternating interval timer.
How results are calculated
Current interval, remaining time and completed rounds.
Accuracy, limitations and fair comparisons
Browser scheduling, device and input differences influence results; recreational only. The challenge runs in your current browser session; compare repeated attempts on the same device for a more useful personal reference.
Questions and answers
Is Interval Timer free?
Yes. This activity is free and does not require registration.
Does this test upload my input or score?
No. Gameplay and optional history storage run in your browser on this device; exporting a result requires your own action.
What is the measured result?
Current interval, remaining time and completed rounds.
Can the result be treated as a medical or hardware diagnosis?
No. Browser scheduling, device and input differences influence results; recreational only.
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