Sleep Cycle Calculator
Explore approximate 90-minute sleep-cycle intervals for planning bedtime or wake-up time.
Use as a planning estimate
The calculation uses 90-minute intervals for convenience. Real sleep cycles vary, and total sleep need differs by person.
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Getting a useful result
Keep a consistent wake time when practical, allow enough opportunity for sleep, and pay attention to how rested and alert you feel. If you have persistent sleep problems or excessive daytime sleepiness, consider speaking with a qualified health professional.