Cycle: 90 min (Sleep + REM)
Ideal: 5 cycles = 7.5 hrs
Time = Target ± (Cycles × 90) + Fall Asleep
Sleep Time Calculator 2025: Optimize Bedtime & Wake-Up
Use **90-minute sleep cycles** to wake up refreshed. Enter age and target time.
Sleep Needs by Age
| Age | Hours/Night | Cycles |
|---|---|---|
| Newborn (0–3 mo) | 14–17 | 9–11 |
| Infant (4–11 mo) | 12–15 | 8–10 |
| Toddler (1–2 yr) | 11–14 | 7–9 |
| Preschool (3–5 yr) | 10–13 | 7–9 |
| School (6–13 yr) | 9–11 | 6–7 |
| Teen (14–17 yr) | 8–10 | 5–7 |
| Adult (18–64 yr) | 7–9 | 5–6 |
| Senior (65+ yr) | 7–8 | 5 |
Sleep Cycle Science
- 90 min: Light → Deep → REM
- Wake mid-cycle → groggy
- Best: End of cycle
Bedtime Tips
- No screens 1 hr before
- Cool, dark room
- Consistent schedule
Wake-Up Hacks
- Sunlight exposure
- Light alarm clock
- Hydrate immediately
Common Myths
- 8 hrs for all — no, varies
- Catch up on weekends — limited
- Naps hurt night sleep — short naps help
Track with Other Tools
FAQs
Can I sleep 6 hrs? Only if you function well.
Best cycle count? 5 (7.5 hrs) for most adults.
Shift workers? Use reverse calculation.
Conclusion
Use our **2025 Sleep Calculator** nightly. Prioritize **consistency** and **quality**.
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