4×4 Interval Timer
4 × 4:00 hard / 3:00 easy · 28 min. Runs in the browser with color-coded phases and beeps; the screen stays on. Free, no sign-up.
Get Ready
0:10
Next: Interval · 4:00
28:10 left
Palette
Space start / pause R reset M mute F fullscreen
How it works
The 4×4 interval session from the Norwegian University of Science and Technology (NTNU) studies: four intervals of four minutes hard with three minutes of easy recovery between them. 28 minutes here; the published protocol adds a warm-up before it.
- Warm up first (not included)
- 4 minutes hard
- 3 minutes easy recovery
- 4 intervals
Work
4:00
Recovery
3:00
Intervals
4
Total
28 min
Pulse for iPhone and Apple Watch
The same kind of timer as an app. Free download; Pulse Pro is $3.99 once. No subscription, no ads.
168 palettes8 free, all 168 with Pro.
Apple WatchSaved interval timers run on the watch, with a haptic at each transition.
Live ActivityThe countdown shows on the Lock Screen and in the Dynamic Island.
Saved timers3 free, unlimited with Pro. Flow sessions, labels and history.
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