◑ HEALTH Updated July 25, 2026

Sleep Calculator

Bedtimes and wake times by sleep cycle.

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How it works

A full sleep cycle averages 90 minutes. Waking at the end of a cycle rather than mid-cycle usually feels far less groggy. Fifteen minutes are added to fall asleep.

Related tools

◕BMR Calculator◈Calorie Calculator▣Body Fat Calculator

Frequently asked questions

How many cycles do I need?

Five to six cycles, or 7.5 to 9 hours, suits most adults.

Is 90 minutes exact?

It is an average. Cycles range from about 70 to 110 minutes and lengthen through the night.

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