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Sleep Calculator

Calculate optimal sleep and wake times based on 90-minute sleep cycles.


About Sleep Cycles

A complete sleep cycle lasts about 90 minutes and includes:

  1. Stage 1: Light sleep, easy to wake
  2. Stage 2: Body temperature drops, heart rate slows
  3. Stage 3: Deep sleep, body repairs itself
  4. REM: Dreams occur, brain processes memories

Waking between cycles (rather than during deep sleep) helps you feel more refreshed.

Recommended sleep: Adults need 7-9 hours (5-6 cycles) per night.

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