Sleep Cycle Calculator

Find the optimal time to wake up or go to bed to feel refreshed, based on natural sleep cycles.

Understanding Sleep Cycles

Sleep isn't uniform. We cycle through different stages of sleep, including light sleep, deep sleep, and REM (Rapid Eye Movement) sleep. A complete sleep cycle typically lasts about 90 minutes on average.

Waking up at the end of a sleep cycle, rather than in the middle of one (especially deep sleep), can help you feel more rested and less groggy. This calculator helps you plan your sleep to align with these natural rhythms.

How This Calculator Works

  • Sleep Cycle Duration: Assumes an average sleep cycle of 90 minutes.
  • Time to Fall Asleep: It typically takes about 15 minutes to fall asleep. This calculator adds this buffer when calculating bedtimes. You can adjust this value.
  • Recommended Sleep: Most adults need 7-9 hours of sleep, which corresponds to about 5-6 full sleep cycles. This tool provides options for 4 to 6 cycles.

Using the Calculator

  1. Choose your calculation mode:
    • "I want to wake up at:" Select your desired wake-up time, and the calculator will suggest bedtimes.
    • "If I go to bed now / at:" Choose a bedtime (or use the current time), and it will suggest optimal wake-up times.
  2. Adjust the "Time to fall asleep" if needed.
  3. Click "Calculate" to see the suggested times.

Disclaimer: These are estimates based on averages. Individual sleep needs and cycle lengths can vary. This tool is for informational purposes and not medical advice.