Best time to sleep or wake up based on 90-minute sleep cycles
When do you need to be awake? (e.g., for office, exam, etc.)
Your sleep is NOT continuous — it cycles through stages every 90 minutes. Each cycle has 4 stages:
Stage 1 (Light Sleep): 5-10 minutes. Easy to wake up.
Stage 2 (Deeper Sleep): 20 minutes. Heart rate slows.
Stage 3 (Deep Sleep): 20-30 minutes. Hardest to wake. Body repairs.
Stage 4 (REM): 10-15 minutes. Dreams happen. Brain consolidates memory.
| Age Group | Recommended Sleep |
|---|---|
| Newborns (0-3 months) | 14-17 hours |
| Infants (4-11 months) | 12-15 hours |
| Toddlers (1-2 years) | 11-14 hours |
| Preschoolers (3-5 years) | 10-13 hours |
| Children (6-13 years) | 9-11 hours |
| Teenagers (14-17 years) | 8-10 hours |
| Young Adults (18-25 years) | 7-9 hours |
| Adults (26-64 years) | 7-9 hours |
| Older Adults (65+) | 7-8 hours |
✅ Consistent schedule: Same sleep/wake time daily, even weekends
✅ No screens 1 hour before bed: Blue light delays melatonin
✅ Cool, dark room: 18-22°C ideal temperature
✅ No caffeine after 2 PM: Stays in system 6+ hours
✅ Light dinner: Heavy meals disturb sleep
✅ Wind down routine: Reading, meditation 30 min before bed
✅ Avoid alcohol: Disrupts REM sleep cycles
This calculator is for informational and educational purposes only. The results are estimates based on standard formulas and should NOT be used as a substitute for professional medical advice, diagnosis, or treatment.