Sleep Cycle Calculator
Sleep runs in cycles of roughly 90 minutes, moving from light sleep through deep sleep and into REM. Waking at the end of a cycle, when sleep is lightest, generally feels easier than being pulled out of deep sleep mid-cycle.
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Input
Result
- Optimal Bedtimes
- 10:00 PM (6 cycles - 9 hrs sleep) 11:30 PM (5 cycles - 7.5 hrs sleep) 01:00 AM (4 cycles - 6 hrs sleep)
About
What the Sleep Cycle Calculator does
This calculator works backwards or forwards in 90-minute blocks and allows about 15 minutes to fall asleep. The 90-minute figure is an average — individual cycles range from roughly 70 to 120 minutes and vary through the night, so treat the suggestions as a starting point and adjust to what actually leaves you feeling rested.
How it works
Using the Sleep Cycle Calculator
- 1Choose whether you are setting a wake time or a bedtime.
- 2Enter that time.
- 3About 15 minutes is allowed for falling asleep.
- 4Times are stepped in 90-minute cycles from that point.
- 5Several options are shown, usually covering four to six cycles.
Use cases
What people use it for
- Setting an alarm that will not catch you mid-cycle
- Deciding when to go to bed for a fixed early start
- Planning a nap that ends at a light point
- Working out a realistic bedtime for a target sleep length
FAQ
Frequently asked questions
6 related
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