Sleep Cycle Calculator

Sleep cycles repeat approximately every 90 minutes. Waking up at the end of a cycle helps you feel more refreshed.

Sleep Information
Select the time you plan to go to bed
What is a Sleep Cycle?

A sleep cycle lasts about 90 minutes and consists of light sleep, deep sleep, and REM sleep stages. Waking at the end of a cycle helps you feel less tired.

Sleep Stages Explained
Light Sleep (N1-N2)

The transition into sleep. Heart rate and breathing slow down.

Deep Sleep (N3)

Physical recovery occurs. Waking during this stage causes grogginess.

REM Sleep

The dreaming stage. Important for memory consolidation and learning.

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Recommended Wake Times

Click a time to set an alarm

Optimal Time Recommendations
Sleep Duration Summary
Sleep Cycles Duration Sleep Quality
4 cycles 6 hrs Minimum
5 cycles 7.5 hrs Good
6 cycles 9 hrs Optimal

About Sleep Cycles

What is a Sleep Cycle?

A sleep cycle is the pattern your body goes through during sleep, consisting of light sleep, deep sleep, and REM (Rapid Eye Movement) sleep. Each cycle takes approximately 90 minutes. Waking up at the end of a cycle helps you feel more refreshed.

  • Each cycle consists of light sleep, deep sleep, and REM sleep
  • Waking up at the end of a cycle helps you feel more refreshed
  • Adults typically need 5-6 cycles (7.5-9 hours) of sleep
How to Use

1. Select either bedtime or wake time mode. 2. Enter your desired time. 3. It takes about 14 minutes to fall asleep on average. 4. Check the recommended times aligned with complete sleep cycles.

  1. Bedtime mode: Enter your bedtime to find optimal wake times
  2. Wake time mode: Enter your wake time to find optimal bedtimes
  3. Consider the time it takes to fall asleep for more accurate results
Tips & Limitations

For optimal rest, aim for 5-6 complete sleep cycles (7.5-9 hours). Avoid caffeine 6 hours before bedtime. Keep your room dark and cool for better sleep quality.

  • Go to bed and wake up at the same time every day
  • Avoid caffeine 2-3 hours before bedtime
  • Keep your bedroom dark and cool
  • Reduce smartphone or computer use before bed