Sleep Cycle Calculator
Calculate the best time to wake up or go to bed to feel refreshed, based on 90-minute sleep cycles.
This tool provides general health information and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
The Science of Sleep Cycles
Human sleep occurs in cycles of approximately 90 minutes. Waking up in the middle of a deep sleep cycle leads to grogginess (sleep inertia). Waking up at the end of a cycle ensures you feel refreshed and alert.
Recommendations
Most adults need 5-6 full cycles (7.5 to 9 hours) of sleep per night.
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