Sleep Calculator
Find the best time to go to bed — or to wake up — based on 90-minute sleep cycles.
To wake at 07:00, go to bed at 23:16
21:46
6 sleep cycles
9h 14m in bed
23:16
5 sleep cycles
7h 44m in bed
00:46
4 sleep cycles
6h 14m in bed
02:16
3 sleep cycles
4h 44m in bed
Based on 90-minute sleep cycles plus about 14 minutes to fall asleep. Waking between cycles leaves you feeling more refreshed.
About this sleep calculator
Sleep is made up of cycles that last about 90 minutes each. This calculator works backwards from the time you want to wake up, adding roughly 14 minutes to fall asleep, and lists bedtimes that put you at the end of a full cycle. Switch to the bedtime mode to see the wake-up times that follow from going to bed now. Related tools: alarm clock, timer, online clock, time calculator.