Wake up refreshed by timing your sleep cycles perfectly. Our calculator uses 90-minute sleep cycles to find your optimal bedtime.
Sleep occurs in cycles of approximately 90 minutes. Each cycle includes light sleep, deep sleep, and REM (rapid eye movement) sleep. Waking up at the end of a cycle, rather than in the middle, helps you feel more refreshed and alert.
Most adults need 4-6 complete sleep cycles per night (6-9 hours). The calculator adds 15 minutes to account for the time it takes to fall asleep, ensuring you wake up at the right moment in your sleep cycle.
Waking up in the middle of deep sleep can leave you feeling groggy and disoriented (sleep inertia). By timing your wake-up to coincide with the end of a sleep cycle, you're more likely to wake up feeling energized.
While this calculator helps you find optimal bedtimes, maintaining a consistent sleep schedule is equally important. Try to go to bed and wake up at the same time every day, even on weekends.