buncha.tools
buncha/time & productivity/sleepcycle

Sleep Cycle Calculator

Sleep happens in 90-minute cycles. Waking at the end of a cycle leaves you feeling rested. Adults typically need 5–6 cycles per night.
Wake time
Time to fall asleep15 min
You should go to bed at
9:45 PM
9h sleep · 6 cycles
Recommended
11:15 PM
7h 30m sleep · 5 cycles
Recommended
12:45 AM
6h sleep · 4 cycles
2:15 AM
4h 30m sleep · 3 cycles
Adults: 5–6 cycles ideal. Teens: 5–6 cycles. Less than 4 cycles regularly may impact health.

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About Sleep Cycle Calculator

Calculate the best time to wake up or go to bed based on 90-minute sleep cycles.

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