πŸ—“οΈ Lifespan Lab

Sleep calculator

Waking up between sleep cycles, not in the middle of one, can make mornings feel easier. Pick a wake-up time or sleep now.

I want to wake up at

Go to bed at one of these times:

If I go to sleep now

Wake up at one of these times:

Includes about 15 minutes to fall asleep. Each sleep cycle is about 90 minutes.

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How it works

Sleep runs in cycles of about 90 minutes. Waking at the end of a cycle often feels easier than waking from deep sleep. The calculator counts back (or forward) whole cycles and adds about 15 minutes to fall asleep.

How much sleep do adults need?

Most adults need about 7–9 hours, which is 5 or 6 cycles. Cycle length differs from person to person, so treat the times as a starting point.

General information, not medical advice.

FAQ

How long is a sleep cycle?

About 90 minutes on average, but it varies between 70 and 120 minutes.

Why add 15 minutes?

Most people take 10–20 minutes to fall asleep.