😴 Sleep Calculator
Enter the time you need to wake up — we calculate ideal bedtimes based on 90-minute sleep cycles.
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💡 Each sleep cycle lasts ~90 minutes. Waking between cycles helps you feel alert. 15 min to fall asleep is already included.
How does the sleep calculator work?
Sleep happens in 90-minute cycles. Waking at the end of a cycle — rather than in the middle — is what makes you feel alert instead of groggy.
How many sleep cycles do I need?
Most adults need 5–6 cycles per night (7.5–9 hours). The calculator shows options from 3 to 6 cycles.
What if I can't fall asleep right away?
The calculator already adds 15 minutes for falling asleep. If you need longer, go to bed a bit earlier.