😴 Sleep Calculator
Calculate optimal bedtime and wake-up time based on sleep cycles.
About Sleep Calculator
Optimize your sleep schedule based on 90-minute sleep cycles. Calculate the best bedtime or wake-up time to wake up refreshed between sleep cycles. Improve sleep quality with science-based timing.
Features
- Wake-up or bedtime modes
- 90-minute cycle timing
- Snooze allowance
Frequently Asked Questions
What are sleep cycles?
Sleep occurs in 90-minute cycles of light sleep, deep sleep, and REM sleep. Waking at the end of a cycle (not in the middle) leaves you feeling more refreshed.
How many sleep cycles per night?
Most adults need 5-6 complete sleep cycles per night (7.5-9 hours). 4 cycles (6 hours) is the minimum for basic function, while 6 cycles (9 hours) is optimal.
What is the best time to sleep?
The best bedtime is one that allows 5-6 complete sleep cycles before your desired wake time. Our calculator works backwards from your wake-up time to find ideal bedtimes.