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
Sleep Quality Score Calculator
A 0-100 composite score across the four most clinically meaningful sleep dimensions.
- Quality score88 / 100
- Duration30 / 30
- Sleep latency25 / 25
- Awakenings15 / 20
- Feeling refreshed18 / 25
- StatusGood — minor optimizations possible
Sleep Consistency Calculator
Enter the past 7 nights to score how consistent your sleep timing is. Sub-30-minute variation is the gold standard.
- Bedtime variation±33 min
- Wake variation±35 min
- Consistency score59 / 100
- StatusPoor consistency — biggest single lever for sleep quality
Weekly Sleep Tracker
Log a night in seconds. Data stays on this device only — nothing is sent to a server.
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).