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Sleep Calculator
Calculate your ideal bedtime based on 90-minute sleep cycles. Wake up at the end of a cycle to feel refreshed — not groggy.
Your ideal bedtimes:
💡 We add ~15 minutes for the average time it takes to fall asleep.
How it works
Sleep happens in 90-minute cycles. Each cycle takes you through light sleep, deep sleep, and REM (dream) sleep.
Waking up between cycles (rather than in the middle of one) is the key to feeling refreshed. That's why 6 hours of sleep can sometimes feel better than 7 — you woke at the right moment.
This calculator finds the optimal bedtimes that align your wake-up time with the end of a complete sleep cycle. We recommend 5-6 cycles (7.5–9 hours) for most adults.
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