Sleep cycle calculator

Plan bedtimes or wake times around 90-minute sleep cycles.

Calculated in this browser. Nothing is sent anywhere.

Suggestions assume 90-minute average cycles plus your fall-asleep buffer. Real cycle length varies per person and per night — treat these as starting points, not medical guidance.

How to use

  1. Pick whether the wake time or bedtime is fixed.
  2. Enter the time and your fall-asleep minutes.
  3. Choose a suggested time by cycle count.

What it supports

Assumes an average 90-minute cycle plus your fall-asleep buffer. Real cycles vary; use as a planning hint, not medical guidance.

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