Sleep Calculator
Calculate the best times to wake up or go to sleep based on 90-minute sleep cycles. Wake up between cycles to feel refreshed.
๐ด Sleep Calculator
Go to sleep at
4 cycles (6.3h)00:45
5 cycles (7.8h)23:15
6 cycles (9.3h)21:45
7 cycles (10.8h)20:15
๐ก How Sleep Cycles Work
Sleep occurs in 90-minute cycles of light sleep โ deep sleep โ REM. Waking mid-cycle (especially during deep sleep) causes grogginess. Waking between cycles feels natural and refreshing.
The calculator adds 15 minutes for falling asleep. Most adults need 4-6 complete cycles (6-9 hours). 5 cycles (7.5 hours) is optimal for most people.
Want to wake at 7:00 AM? Best sleep times: 11:15 PM (5 cycles, 7.75h), 9:45 PM (6 cycles, 9.25h), or 12:45 AM (4 cycles, 6.25h).