Sleep Cycle Calculator
Calculator ToolsBest bedtime based on 90-minute cycles
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History
All history →Sleep Cycle Calculator — at a glance
Wake up fresher by timing your sleep in 90-minute cycles.
Wake at 6:30 AM
Run
Sleep at 9:15 PM (6 cycles)
How to use it — step by step
The time you want to wake up and how long you usually take to fall asleep.
1
Enter your values
Fill in the boxes. Sensible example values are already filled in for you.
2
Find Bedtimes
Press the button. The answer is worked out instantly on your device.
3
Read or copy the result
See the big answer and the extra details, then press Copy to keep them.
Pro tips
Small things that make the result better.
✦Aim for 5–6 cycles (7.5–9 hours) on most nights.
✦Keep the same wake-up time every day, even on weekends.
✦Avoid screens for 30 minutes before the bedtime shown.
Quick facts
90 minper sleep cycle
4 options3 to 6 cycles
Fall asleeptime included
Freeno signup
Frequently Asked Questions
Is a 90-minute cycle exact?+
It is an average. Real cycles vary between about 80 and 110 minutes from person to person.
Is this medical advice?+
No. If you have long-term sleep problems, speak with a doctor.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
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