About the Sleep Cycle Calculator
Tell it when you need to wake up (or when you're going to bed) and get recommended times aligned to complete 90-minute sleep cycles, including the ~15 minutes an average person takes to fall asleep.
Waking at the end of a cycle instead of mid-cycle is the difference between refreshed and groggy.
How to use the Sleep Cycle Calculator
- Choose mode: "I need to wake at…" or "I'm going to bed now".
- Set the time.
- Pick one of the suggested times aligned to full cycles.
Common uses
Planning bedtime before an early start
Optimizing naps and irregular schedules
Improving morning grogginess
Frequently asked questions
Why 90-minute cycles?
Sleep moves through light, deep and REM stages in roughly 90-minute cycles; waking between cycles feels easiest.
How many cycles do adults need?
Five to six cycles (7.5–9 hours) suits most adults.
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