Sleep Cycle Calculator
Find the best times to sleep or wake based on 90-minute sleep cycles.
To find the best time to sleep or wake, enter your target time. Sleep runs in roughly 90-minute cycles, and waking at the end of a cycle rather than mid-cycle usually feels less groggy. An extra 15 minutes is added for the time it takes to fall asleep.
Runs in your browser- Privacy
- Runs entirely in your browser — nothing is uploaded
- Cost
- Free, unlimited, no sign-up
Frequently asked questions
Are sleep cycles really 90 minutes?
How to use the sleep cycle calculator
- 1Enter or paste your time.
- 2Choose the i want to.
- 3The result appears immediately — copy or download it.
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Put the working sleep cycle calculator on your own site. It runs in your visitors' browsers exactly as it does here — free, no account, nothing uploaded.
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