everyday-health Verified Precision Tool
Sleep Cycle & Bedtime Calculator
Calculate optimal bedtimes and wake times based on 90-minute REM sleep cycles.
Mathematical Formula
Sleep Cycle = 90 minutes + 15 min fall-asleep delay
Overview & Explanation
Sleep cycle calculators structure rest intervals around natural 90-minute REM cycles to prevent grogginess.
How It Works
- Subtracts multiples of 90 minutes from target wake-up time.
- Adds 15 minutes average time to fall asleep.
Practical Applications
- Bedtime optimization.
- Avoiding sleep inertia.
Wake up at 07:00 AM
Calculate 5-cycle bedtime.
1
Calculate 5 cycles (7.5 hours)
7.5 hrs + 15 min delay
= 7 hours 45 mins prior
2
Subtract from 07:00 AM
07:00 - 7h45m
= 11:15 PM Bedtime
Frequently Asked Questions
How many sleep cycles per night are recommended?
Most healthy adults require 5 to 6 completed sleep cycles per night (7.5 to 9 hours).
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