Sleep Cycle Calculator
Find optimal wake times based on 90-minute sleep cycles to wake up feeling refreshed.
Sleep Cycles
Bedtime
10:30 PM
1 Cycle (1h 30m)
12:00 AM
2 Cycles (3h 0m)
01:30 AM
3 Cycles (4h 30m)
03:00 AM
4 Cycles (6h 0m)
04:30 AM
5 Cycles (7h 30m)
06:00 AM
6 Cycles (9h 0m)
07:30 AM
About Sleep Cycles
90-Minute Cycles:
Sleep occurs in cycles of approximately 90 minutes, alternating between REM and non-REM sleep. Waking at the end of a cycle (during light sleep) feels more natural than waking during deep sleep. Most people need 5-6 complete cycles (7.5-9 hours) for optimal rest.
Optimal Wake Times:
Cycles 5-6 (7.5-9 hours) are typically optimal for most adults. Waking during these cycles reduces grogginess and improves alertness. Individual needs vary, so experiment to find what works best for you.
Improves TDEE accuracy if known