Sleep Cycle Calculator
Find the best bedtimes to wake between sleep cycles.
Wake between cycles
Sleep moves through roughly 90-minute cycles, and waking at the end of one — rather than being jolted out of deep sleep mid-cycle — tends to feel far more refreshing. Timing bedtime to complete cycles helps.
Enter your wake-up time and it counts back full 90-minute cycles, plus 15 minutes to fall asleep, to suggest bedtimes. Aiming for five or six complete cycles is the sweet spot for most adults.
Restful and private
The calculation runs in your browser, so nothing you enter is uploaded.
Frequently Asked Questions
How do sleep cycles work?
Sleep runs in roughly 90-minute cycles. Waking at the end of a cycle, rather than mid-cycle, tends to feel more refreshing.
What does the tool assume?
About 15 minutes to fall asleep, and full 90-minute cycles. It suggests bedtimes for five and six complete cycles.
Is 90 minutes exact for everyone?
No. Cycle length varies a little between people, so use the suggestions as a helpful guide.
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