Sleep Calculator
💤 Note: This calculator estimates optimal sleep/wake times based on 90-minute sleep cycles. Individual sleep needs vary — consult a doctor for persistent sleep issues.
Calculate the best time to go to bed or wake up based on natural 90-minute sleep cycles, so you wake up feeling refreshed instead of groggy.
Frequently Asked Questions
Why does sleep come in 90-minute cycles?
A full sleep cycle (light sleep, deep sleep, REM) lasts about 90 minutes. Waking up at the end of a cycle, rather than in the middle, helps you feel more refreshed.
How many sleep cycles should I aim for?
Most adults need 5-6 complete cycles per night, which equals about 7.5 to 9 hours of sleep.
Is this calculator medically accurate?
It's based on average sleep cycle research and provides a helpful estimate, but individual sleep patterns vary. Consult a doctor for chronic sleep issues.