About This Tool
This Sleep Calculator helps you find the perfect bedtime or wake up time based on your body's natural 90 minute sleep cycles. Waking up at the end of a sleep cycle means you feel more refreshed and energized.
How To Use
- Choose whether you want to set a wake up time or a bedtime
- Enter your preferred time
- Click the calculate button
- Pick the best time from the results
What Are Sleep Cycles?
Your sleep is divided into cycles of approximately 90 minutes each. Each cycle includes light sleep, deep sleep and REM sleep. Waking up in the middle of a cycle makes you feel groggy and tired. This tool calculates times that land exactly at the end of a cycle so you wake up naturally feeling refreshed.
Frequently Asked Questions
Yes, this tool is completely free to use with no limits.
Most adults need 6 to 9 hours of sleep. This tool shows options for 4, 5, 6 and 7 complete sleep cycles.
On average it takes a person about 14 minutes to fall asleep after lying down. This tool includes that time in the calculation.
Yes, this tool works perfectly on both mobile and desktop devices.