⏱️ Sleep Cycle Calculator — 90-Minute Estimate
Pick a bedtime or a wake time and get nearby cycle estimates. This is a planning aid, not medical advice.
How it works
- Choose whether you know bedtime or wake time, then enter a 24-hour clock time.
- Press Calculate. Each suggestion adds 15 minutes to fall asleep plus 3 to 6 cycles of 90 minutes.
- Use the list as an estimate. Individual sleep length varies.
Examples
- Bedtime 23:00 suggests a 04:45 wake time after four cycles.
- Wake time 07:00 suggests a 00:15 bedtime for five cycles.
- Six cycles from 22:30 lands at 07:45 the next morning.
Frequently asked questions
Why 90 minutes?
A commonly cited average adult cycle is about 90 minutes. The tool uses that fixed estimate plus 15 minutes to fall asleep. It is not a measurement of your sleep.
Is this medical advice?
No. It only does clock arithmetic so you can plan a consistent schedule. Talk to a clinician for sleep problems.
Are times uploaded?
No. The suggestions are calculated in the browser.
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