How does the sleep calculator work?

It calculates optimal sleep or wake times by counting backwards or forwards in 90-minute sleep cycles, plus 15 minutes to fall asleep.

How long is a sleep cycle?

A typical sleep cycle lasts about 90 minutes. Waking up at the end of a cycle helps you feel more refreshed and avoid sleep inertia.

Calculate the best times to go to sleep or wake up based on 90-minute sleep cycles.

Settings

I want to calculate:

What time do you want to wake up?

We automatically add 15 minutes to account for the average time it takes to fall asleep.

Sleep Cycle Facts

A typical sleep cycle lasts about 90 minutes.
Most adults need 5 to 6 sleep cycles per night (7.5 to 9 hours of sleep).
Waking up in the middle of a cycle can leave you feeling tired and groggy (sleep inertia).

Recommended Bedtimes

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