Sleep Calculator
Find the perfect bedtime or wake-up time based on 90-minute sleep cycles
🕐 Average time to fall asleep:
15 minutes
Recommended Times
Why 90-minute cycles?
Your sleep cycles between light, deep, and REM sleep last about 90 minutes. Waking up between cycles (rather than during deep sleep) helps you feel more rested. For most adults, 5-6 complete cycles (7.5-9 hours) is optimal.
Your sleep cycles between light, deep, and REM sleep last about 90 minutes. Waking up between cycles (rather than during deep sleep) helps you feel more rested. For most adults, 5-6 complete cycles (7.5-9 hours) is optimal.
About this Calculator
The Sleep Calculator helps you find the ideal bedtime or wake-up time based on 90-minute sleep cycles. Instead of waking up groggy in the middle of a deep sleep phase, use this calculator to plan sleep and wake times that align with your natural sleep rhythms. Simply enter your desired wake-up time or bedtime to see all recommended options.
Privacy Note:
All calculations are performed locally in your browser. No data is ever sent to a server or third party.