11:11 AM
11:11 (24h)
3 cycles · 4.5h sleep
⚠️ Short, for naps only
Sleep Cycle Calculator
Wake up between cycles, not in the middle of one. 90 minutes per cycle + 14-minute fall-asleep buffer.
If you go to sleep now, wake up at:
12:41 PM
12:41 (24h)
4 cycles · 6h sleep
✅ Sufficient
2:11 PM
14:11 (24h)
5 cycles · 7.5h sleep
✨ Ideal for adults
3:41 PM
15:41 (24h)
6 cycles · 9h sleep
✨ Ideal for adults
Why 90 minutes?
Your brain cycles through light sleep, deep sleep, and REM in approximately 90-minute intervals. Waking up between cycles feels natural, whereas waking mid-cycle causes grogginess (sleep inertia).
- • 5 cycles (7.5h) — recommended for most adults.
- • 6 cycles (9h) — ideal if recovering from sleep debt.
- • 4 cycles (6h) — minimum for cognitive function.
- • 3 cycles (4.5h) — power sleep; avoid if possible.