Sleep Tools
Free Sleep Tools
Mobile-optimized, science-backed sleep calculators. No sign-up required.
Sleep Calculator
Find the best bedtimes based on 90-minute sleep cycles and the time you need to wake up.
- 6 cycles (9.0h sleep)9:46 PMRecommended
- 5 cycles (7.5h sleep)11:16 PMRecommended
- 4 cycles (6.0h sleep)12:46 AM
- 3 cycles (4.5h sleep)2:16 AM
Bedtime Calculator
Enter your wake-up time and we'll tell you when to be asleep.
- Optimal bedtime (7.5h sleep)10:46 PM
- Better bedtime (9h sleep)9:16 PMRecommended
Sleep Cycle Calculator
If you go to bed now, here are the best times to wake up between sleep cycles.
- 4 cycles (6.0h)5:14 AM
- 5 cycles (7.5h)6:44 AMRecommended
- 6 cycles (9.0h)8:14 AMRecommended
Sleep Duration Calculator
Calculate exactly how many hours you spend in bed and how it compares to the recommended 7–9 hours.
- Time in bed7.5 h
- StatusOptimal sleep duration
Sleep Efficiency Calculator
Sleep efficiency is the percentage of time in bed you spend actually asleep. 85% or higher is the clinical target.
- Time in bed8.0 h
- Sleep efficiency81%
- StatusFair — room to improve
Sleep Debt Calculator
Estimate the sleep debt you've accumulated over the past 7 nights.
- Total sleep needed56.0 h
- Total sleep actual49.0 h
- Sleep debt7.0 hCatch up gradually
How our sleep calculators work
The average adult sleep cycle lasts about 90 minutes and includes light sleep, deep sleep and REM stages. Waking up at the end of a cycle — rather than in the middle — helps you feel refreshed instead of groggy.
Our calculators assume an average of 14 minutes to fall asleep (the typical adult sleep latency) and build schedules around complete 90-minute cycles. Most adults function best on 5 to 6 cycles per night (7.5 to 9 hours).