Sleep Calculator
Wake up between sleep cycles, not in the middle of one. Find the bedtimes or wake times that fit.
Awaiting Data
Enter your details and tap Calculate to see your results appear here.
Your result appears here.
Why Sleep Cycles Matter
Sleep moves through cycles of about 90 minutes. Waking at the end of a cycle feels easy, while waking mid-cycle leaves you groggy.
This tool counts back or forward in full cycles, then adds 15 minutes to fall asleep. Aim for five or six cycles a night.
Pick a wake time and it lists the best bedtimes, or choose to sleep now and see ideal wake times.
How to Use This Calculator
- Choose your mode.
- Enter your target wake time, or pick sleep now.
- Tap Calculate for the best times.
The Formula Used
Cycles = 6, 5, or 4
- cycle
- About 90 minutes of sleep.
- 15 min
- Average time to fall asleep.
Understanding Your Results
Tips to Improve
- Keep a steady sleep and wake schedule.
- Dim screens an hour before bed.
- Keep the room cool and dark.
- Avoid caffeine late in the day.
Frequently Asked Questions
About 90 minutes on average, though it varies a little between people.
Five or six cycles, around seven and a half to nine hours, suits most adults.
Waking mid-cycle, especially in deep sleep, causes that heavy feeling.
Scientific References
- Carskadon, M. A., & Dement, W. C. (2017). Normal human sleep. In Principles and Practice of Sleep Medicine (6th ed.).
- Hirshkowitz, M., et al. (2015). National Sleep Foundation sleep duration recommendations. Sleep Health, 1(1), 40–43.
- Walker, M. (2017). Why We Sleep. Scribner.