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Sleep Calculator

Enter your wake-up time to see the best bedtimes.

Waking in the middle of a deep sleep cycle leaves you groggy; waking at the end of one feels natural. Sleep runs in roughly 90-minute cycles, so this counts back from your wake-up time to suggest bedtimes that let you complete 4, 5 or 6 full cycles — plus about 15 minutes to drift off. Aim for 5 to 6 cycles a night.

Sleep better
Rest easy.
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Frequently asked questions

How long is a sleep cycle?

About 90 minutes on average, though it varies by person and across the night. Completing whole cycles is why waking after 6 or 7.5 hours can feel easier than after 7.

How many cycles do I need?

Most adults do well on 5 to 6 cycles, which is roughly 7.5 to 9 hours. Consistency of bed and wake times matters as much as the total.