Sleep Cycle Calculator
Find the best bedtime based on 90-minute sleep cycles.
Each option ends a full 90-minute sleep cycle at your wake-up time.
Includes ~15 minutes to fall asleep; individual cycles vary between 80–100 minutes.
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AHow to use
- 01 Enter the time you need to wake up.
- 02 Choose a bedtime: more cycles means more sleep.
- 03 Waking at the end of a cycle is when you feel most refreshed.
QFAQ
Why 90-minute cycles? ＋
Sleep runs in roughly 90-minute cycles of light, deep and REM sleep. Waking at the end of a cycle, in light sleep, feels far easier than mid-deep-sleep.
What is the 15-minute allowance? ＋
The average time it takes to fall asleep. The listed bedtimes include it, so the cycle count starts when you actually drift off.