Fall asleep in15 min
Go to bed at one of these times:
How it works
Sleep happens in 90-minute cycles. Each cycle moves through light sleep, deep sleep, and REM.
Waking up between cycles (rather than mid-cycle) helps you feel alert instead of groggy. Slumber calculates optimal times based on complete cycles.
Adults need 5\u20136 cycles (7.5\u20139 hours) per night. 4 cycles (6 hours) is the minimum for most people.
Caffeine & sleep
Caffeine has a half-life of 5\u20136 hours. To avoid disrupting sleep onset and deep sleep, stop caffeine at least 8 hours before bedtime.
The caffeine cutoff shown above your results is calculated from your target bedtime.
Recommended sleep by age
Teens (14–17)8–10h
Young adults (18–25)7–9h
Adults (26–64)7–9h
Older adults (65+)7–8h