Sleep Calculator
Find your optimal bedtime and wake-up time based on 90-minute sleep cycles.
1Bedtime
2Recommended Sleep by Age
| Age Group | Sleep | Cycles |
|---|---|---|
| Newborn (0-3 mo) | 14-17h | - |
| Infant (4-11 mo) | 12-15h | - |
| Toddler (1-2 yr) | 11-14h | - |
| Preschool (3-5 yr) | 10-13h | - |
| School age (6-13 yr) | 9-11h | 6-7 |
| Teen (14-17 yr) | 8-10h | 5-6 |
| Young adult (18-25) | 7-9h | 5-6 |
| Adult (26-64) | 7-9h | 5-6 |
| Older adult (65+) | 7-8h | 5 |
Sleep Guide
Understanding Sleep Cycles: Sleep consists of repeating ~90-minute cycles of NREM stages 1-3 and REM sleep. Deep sleep (NREM 3) is for physical recovery, while REM sleep handles memory consolidation and learning. Waking at the end of a cycle (after REM) feels refreshing; waking during deep sleep causes grogginess.
Improving Sleep Quality: The most important factor is a consistent sleep schedule - go to bed and wake up at the same time daily. Avoid caffeine, alcohol, and heavy meals 2 hours before bed. Keep your bedroom dark and cool (65-68°F / 18-20°C). Replace screen time with reading or stretching in the last hour before sleep.
Effects of Sleep Deprivation: Chronic sleep deprivation is linked to reduced concentration, weakened immunity, obesity, and increased cardiovascular risk. Sleeping under 6 hours for 2+ weeks causes cognitive decline similar to 48 hours without sleep. Weekend catch-up sleep does not fully repay sleep debt.