Sleep Cycle Calculator

Find the best time to wake up or go to sleep based on natural 90-minute sleep cycles.

Calculate Bedtime

Select the time you want to wake up to find out the best times to fall asleep.

Wake-up Time

The Science of Sleep Cycles

Waking up in the middle of a sleep cycle can leave you feeling groggy and tired, even if you've slept for a long time. Our sleep is made up of several 90-minute cycles. By waking up at the end of a cycle, you feel more refreshed and alert.

How It Works

This calculator works backward from your desired wake-up time or forward from your bedtime to identify the ideal times to sleep or wake. It accounts for the average 14 minutes it takes for a person to fall asleep.

Calculate Bedtime: If you know when you need to wake up, select "I want to wake up at..." and enter the time. The calculator will tell you the best times to go to bed to complete a full number of sleep cycles.
Calculate Wake-up Time: If you're going to bed now or at a specific time, select "I want to go to bed at..." and enter the time. It will suggest several optimal wake-up times.

For optimal rest, most adults need 5-6 full sleep cycles, which translates to 7.5-9 hours of sleep per night.