😴 Sleep Calculator
Find the best bedtime or wake-up time to complete full sleep cycles and wake up refreshed.
Sleep Mode
Recommended Bedtimes
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Sleep Cycles Explained
Sleep occurs in 90-minute cycles consisting of light sleep, deep sleep (slow-wave), and REM (rapid eye movement) sleep. Waking up between cycles — rather than in the middle of deep sleep — leaves you feeling more rested even with fewer hours.
Recommended Sleep by Age (NSF)
| Age | Recommended Hours |
|---|---|
| Newborn (0–3 mo) | 14–17 hours |
| School age (6–13) | 9–11 hours |
| Teens (14–17) | 8–10 hours |
| Adults (18–64) | 7–9 hours |
| Older adults (65+) | 7–8 hours |