Sleep Cycle Calculator

Calculate optimal wake times based on your bedtime

Understanding Sleep Cycles

A complete sleep cycle typically lasts about 90 minutes and consists of four stages: light sleep, deeper sleep, deep sleep (slow-wave sleep), and REM sleep. Waking up during a light sleep stage (at the end of a cycle) will leave you feeling more refreshed than waking during deep sleep.

Our calculator shows you multiple wake time options based on completing 4, 5, or 6 full sleep cycles. Each cycle is approximately 90 minutes, so:

  • 4 cycles: 6 hours of sleep
  • 5 cycles: 7.5 hours of sleep
  • 6 cycles: 9 hours of sleep

Choose the wake time that best fits your schedule while ensuring you wake up during a light sleep phase for optimal alertness.