😴 Sleep Calculator
Calculate optimal sleep and wake times based on sleep cycles
About Sleep Cycles
Sleep occurs in 90-minute cycles. Waking at the end of a cycle helps you feel more refreshed than waking mid-cycle.
Recommended Sleep Duration
- Adults (18-64): 7-9 hours (5-6 cycles)
- Older Adults (65+): 7-8 hours (5 cycles)
- Teenagers: 8-10 hours (6 cycles)
Frequently Asked Questions
Why 90-minute cycles?
A complete sleep cycle lasts about 90 minutes, including all sleep stages from light to deep to REM sleep.
What if I can't sleep 7-9 hours?
Aim for complete cycles. 6 hours (4 cycles) is better than 7 hours if it means waking mid-cycle.