Sleep Cycle Calculator
Wake up between sleep cycles instead of in the middle of one. Choose when you need to wake up (or when you’re going to bed) and get the best times.
Your result appears here.
By Shah Rukh, software developer · Last updated:
How sleep cycles work
Sleep runs in cycles of roughly 90 minutes, moving through light sleep, deep sleep and REM (dreaming) sleep. Waking at the end of a cycle usually feels easier than being woken from deep sleep.
How much sleep do you need?
- Adults: 7–9 hours (about 5–6 cycles).
- Teenagers: 8–10 hours.
The calculator adds about 15 minutes to fall asleep. Everyone is different, so adjust if you tend to fall asleep faster or slower.
Frequently asked questions
Is a sleep cycle always 90 minutes?
It averages about 90 minutes but varies from roughly 70 to 120 minutes between people and through the night.
Is 6 hours of sleep enough?
Most adults need 7–9 hours. Regularly sleeping less can affect mood, focus and health.
Why do I wake up groggy?
Waking from deep sleep causes sleep inertia. Waking between cycles and keeping a regular schedule helps.
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