Sleep Calculator

90-minute sleep cycles, bedtime/wake planner, hours slept, power naps, and age-based sleep recommendations.

How It Works

  1. Choose wake or bedtime. Enter the hour, minute, and AM/PM for your target time.
  2. Get cycle times. 90-minute cycles back-calculate the best bedtime or wake time (5?6 cycles).
  3. Tune cycle settings. Adjust cycle length and minutes to fall asleep.
  4. Hours slept & length. Calculate total sleep between two times or plan a fixed duration.
  5. Naps & age guide. Power nap end times and recommended hours by age.

Also try our Steps to Miles Calculator or Fitness & Health Calculators.

Enter values to see results.

Formula & Reference

Bedtime = Wake − (cycles × 90) − fall-asleep