Sleep Calculator
Find the best time to go to sleep or wake up based on 90-minute sleep cycles. Helps you wake up feeling refreshed.
How the Sleep Calculator Works
A full sleep cycle lasts approximately 90 minutes. The calculator suggests bedtimes (or wake times) that align with complete cycles, so you're more likely to wake during light sleep rather than deep sleep.
Recommended Sleep Duration
| Age Group | Hours Needed |
|---|---|
| Adults (18–64) | 7–9 hours |
| Teens (14–17) | 8–10 hours |
| School-age (6–13) | 9–11 hours |
| Older adults (65+) | 7–8 hours |
Tips for Better Sleep
- Allow 15 minutes to fall asleep (factored into calculations).
- Keep a consistent sleep schedule.
- Avoid screens 30–60 minutes before bed.
- Keep the room cool (18–20°C / 65–68°F).
FAQ
Why 90-minute cycles?
Each sleep cycle progresses through light sleep, deep sleep, and REM sleep. Waking between cycles (rather than in deep sleep) helps you feel more alert.
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Last updated: 2026-08-08