Free tool

Sleep Cycle Bedtime Calculator

Enter your target wake-up time or bedtime and get recommended sleep and wake times based on 90-minute sleep cycles.

Recommended bedtimes for a 7:00 AM wake-up

  • 9:46 PM6 cycles · 9.0 hrs
  • 11:16 PM5 cycles · 7.5 hrsbalanced
  • 12:46 AM4 cycles · 6.0 hrs

Based on 90-minute sleep cycles plus ~14 minutes to fall asleep.

How to use this calculator

Choose whether you want to find a bedtime (given a fixed wake-up time) or a wake time (given a fixed bedtime). Enter your time and the calculator returns three options: 4, 5, and 6 complete sleep cycles. The 5-cycle option (7.5 hours) is highlighted as a balanced default for most adults.

Understanding your result

Each result shows a recommended time alongside the number of cycles and total sleep hours. Waking at the natural end of a cycle — rather than mid-cycle — is associated with feeling more rested. The times include an estimated 14 minutes to fall asleep, so your actual lights-out time is a few minutes before the displayed bedtime.

Disclaimer

This calculator provides estimates for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Sleep needs vary between individuals. If you have ongoing sleep problems, fatigue, or a suspected sleep disorder, consult a qualified healthcare provider.

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Frequently asked questions

Why 90-minute sleep cycles?

Sleep is structured in roughly 90-minute cycles, each moving through light sleep, deep sleep, and REM. Waking at the end of a cycle — rather than mid-cycle — tends to feel more refreshing. The 90-minute figure is an average; individual cycles range from about 80 to 100 minutes.

How many sleep cycles do I need?

Most adults feel best after 5 to 6 complete cycles (7.5 to 9 hours). Five cycles (7.5 hours) is a commonly recommended balanced target. Younger adults and teenagers often need more; older adults sometimes do well with slightly less. Your personal needs may vary.

Is this medical advice?

No. This calculator provides estimates for informational purposes only. Always consult a qualified healthcare professional before making decisions about your health.

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