Sleep Calculator
Find the best times to go to sleep or wake up, based on 90-minute sleep cycles.
For a wake-up plan, enter when you need to wake. For a bedtime plan, enter when you'll go to bed.
Sleep runs in cycles of about 90 minutes, and waking at the end of a cycle tends to feel more refreshing than waking mid-cycle. Choose whether you're planning your wake-up or your bedtime, and we'll suggest times built around full cycles (allowing about 15 minutes to fall asleep).
Frequently asked questions
A full sleep cycle — moving through light, deep and REM sleep — lasts roughly 90 minutes on average. Waking at the end of a cycle, rather than in the middle of deep sleep, tends to feel less groggy. The exact length varies between people and nights.
Most adults do well on five to six cycles a night, which is about 7.5 to 9 hours. This calculator highlights those first, but the right amount varies from person to person.