What is Sleep Calculator?
Sleep alternates between light and deep sleep in cycles of about 90 minutes. Waking at the end of a cycle leaves you less tired, so enter when you need to wake up to get bedtimes, or go to bed now to get wake-up times, cycle by cycle. Recommended sleep by age is shown too.
How to use
- 1
Choose wake-up time or bedtime.
- 2
Enter the time and how long it takes you to fall asleep.
- 3
Pick one of the suggested times.
Use cases
Before a workday
See when to go to bed to wake up at 7.
Planning a nap
See when to wake up if you lie down now.
FAQ
Is the information I enter saved?+
No. All calculations happen in your browser and nothing is stored or sent anywhere.