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Health
Sleep Cycle & Optimal Bedtime Calculator
Find the ideal times to fall asleep and wake up refreshed by aligning with natural 90-minute REM sleep cycles.
Parameters
Configure the inputs for precise results.
Awaiting Parameters
Fill in the tool settings and click calculate to see the magic happen.
How to Use
1
Choose Mode
Select whether you want to calculate when to wake up or when to go to bed.
2
Set Reference Time
Enter your target wake-up or bed time.
3
Pick Optimal Cycle
Select from the suggested 5 or 6 cycle sweet spots (7.5h or 9h of sleep).
FAQ
How does the sleep cycle calculator work?
It calculates optimal sleep times in 90-minute cycle increments plus 15 minutes average time needed to fall asleep.
Why do 90-minute sleep cycles matter?
Waking up mid-cycle during deep sleep causes grogginess (sleep inertia), whereas waking up between cycles leaves you feeling naturally alert.