Sleep Calculator
Use this Sleep Calculator to determine the best time to go to bed or the ideal time to wake up based on natural sleep cycles.
The calculator works with 90-minute sleep cycles and your estimated time to fall asleep, helping you wake up between cycles instead of during deep sleep — so you feel more rested and alert.
It also adapts recommendations based on age, making it suitable for adults, teenagers, children, and infants.
About Sleep Cycles
Sleep is divided into repeating cycles that typically last about 90 minutes. Each cycle includes light sleep, deep sleep, and REM (rapid eye movement) sleep. Waking up at the end of a sleep cycle is much easier than waking up during deep sleep, which is why timing matters.
This Sleep Calculator helps you align your bedtime or wake-up time with these natural sleep cycles. By accounting for the time it usually takes you to fall asleep (sleep latency), the calculator suggests optimal sleep and wake times that reduce morning grogginess.
Recommended sleep duration varies by age. Infants and children require more sleep for growth and development, while adults typically function best with 7–9 hours per night. This calculator adjusts cycle recommendations based on your selected age group.
Recommended Sleep Hours by Age
| Age Group | Recommended Sleep (hours) |
|---|---|
| 0–3 months | 14–17 |
| 4–11 months | 12–15 |
| 1–2 years | 11–14 |
| 3–4 years | 10–13 |
| 5–13 years | 9–11 |
| 14–17 years | 8–10 |
| 18–24 years | 7–9 |
| 25–64 years | 7–9 |
| 65+ years | 7–8 |