Sleep Calculator
Find the best times to go to bed or wake up based on 90-minute sleep cycles. Get optimal sleep schedule recommendations.
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How Sleep Cycles Work
A complete sleep cycle lasts about 90 minutes. Waking up at the end of a cycle (rather than in the middle) helps you feel refreshed. The calculator accounts for an average of 15 minutes to fall asleep.
Frequently Asked Questions
What is a sleep cycle?
A complete sleep cycle lasts approximately 90 minutes and includes stages of light sleep, deep sleep, and REM (dream) sleep. Most adults need 4 to 6 complete cycles per night.
Why is waking between cycles better?
Waking up at the end of a sleep cycle (during light sleep) helps you feel refreshed. Waking during deep sleep can cause grogginess and sleep inertia, making you feel tired.
How long does it take to fall asleep?
The average person takes about 10-20 minutes to fall asleep. This calculator uses 15 minutes as the standard estimate. If you regularly take longer, adjust your bedtime accordingly.