Sleep Cycle Calculator
Find the best times to wake up based on 90-minute sleep cycles. Enter your bedtime and get optimal wake-up times so you feel refreshed.
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Frequently Asked Questions
What is a sleep cycle?
A sleep cycle lasts about 90 minutes and includes light sleep, deep sleep, and REM sleep. Waking up at the end of a cycle — rather than in the middle — helps you feel more alert and refreshed.
Why is 15 minutes added to my bedtime?
It takes the average person about 15 minutes to fall asleep after lying down. The calculator adds this buffer so the wake-up times are aligned with complete sleep cycles.
How many sleep cycles should I get?
Most adults need 5–6 complete sleep cycles per night, which equals 7.5–9 hours of sleep. Fewer than 4 cycles (6 hours) is generally considered insufficient for long-term health.