Sleep Cycle Calculator
Optimize your sleep with personalized recommendations
Sleep Stages
Transition from wakefulness to sleep
5-10 minutes
Physical restoration and memory consolidation
45-55 minutes
Dreams and cognitive processing
20-25 minutes
When should I wake up?
Power Nap Timer
Sleep Optimization Tips
About the Sleep Cycle Calculator
Work out the best times to go to bed or wake up so you finish a full sleep cycle instead of being woken in the middle of one. Enter the time you need to wake up and see bedtimes, or enter your bedtime and see wake-up times. There is also a power-nap timer and a set of sleep tips.
How to use it
- 1
Choose your starting point
Select “I know my wake time” to get bedtimes, or “I know my bedtime” to get wake-up times.
- 2
Enter the time
Set the time you must wake up, or the time you plan to go to bed.
- 3
Pick a result
The calculator lists options with the number of sleep cycles and a quality label — five cycles is rated excellent, four or six good.
- 4
Try the nap timer
For a daytime nap, open the Power Nap Timer and choose 10, 20 or 30 minutes.
Good to know
- The calculation assumes an average 90-minute sleep cycle and about 15 minutes to fall asleep. Real sleep varies from person to person and night to night.
- This is general information, not medical advice. If you regularly struggle to sleep or feel exhausted, talk to a doctor.
Frequently asked questions
- How does a sleep cycle calculator work?
- Sleep moves through repeating cycles of roughly 90 minutes. Waking at the end of a cycle usually feels easier than waking in the middle of deep sleep, so the calculator counts back or forward in 90-minute steps, adding about 15 minutes for falling asleep.
- How many cycles of sleep do I need?
- Many adults aim for five or six cycles (about 7.5 to 9 hours), but needs differ. The calculator shows several options so you can choose what fits your day.
- How long should a power nap be?
- Short naps of 10 to 20 minutes are generally recommended because they are less likely to leave you groggy. The timer offers 10, 20 and 30 minutes.
- Is my information stored?
- No. The calculation happens in your browser and the times you enter are not sent anywhere.
Tell us how it worked for you.