Sleep Calculator
Waking up refreshed isn't just about total sleep time - it's about timing. This calculator uses the 90-minute sleep cycle method to find your optimal bedtime.
Wake-up Time
Based on 90-minute sleep cycles
Recommended Bedtimes
About Sleep Calculator
Waking up feeling refreshed isn't just about total sleep time - it's about timing. Our sleep calculator uses the 90-minute sleep cycle method to find the optimal bedtime for your wake-up time.
Aiming for 5 complete cycles (7.5 hours) of sleep is ideal for most adults. Waking at the end of a sleep cycle leaves you feeling more rested than waking mid-cycle.
Sleep Cycle Formula
Bedtime = Wake Time - (90 minutes × Number of Cycles)
Example: Wake at 7:00 AM - 5 cycles (7.5 hours) = 11:30 PM bedtime
Sleep Cycle Science
Light Sleep
Easy to wake, accounts for 50% of sleep
Deep Sleep
Body repairs, difficult to wake
REM Sleep
Dreaming, memory consolidation
Sleep Recommendations by Age
| Age Group | Recommended Sleep |
|---|---|
| Adults (18-64) | 7-9 hours |
| Older Adults (65+) | 7-8 hours |
| Teens (14-17) | 8-10 hours |
| School Children (6-13) | 9-11 hours |
| Preschool (3-5) | 10-13 hours |
Frequently Asked Questions
About the Sleep Calculator
Waking up refreshed isn't just about total sleep time - it's about timing. This calculator uses the 90-minute sleep cycle method to find your optimal bedtime.
Formula
Sleep Recommendations by Age
| Category | Value |
|---|---|
| 4.5 hours | 3 cycles |
| 6 hours | 4 cycles |
| 7.5 hours | 5 cycles |
| 9 hours | 6 cycles |