Find the best times to sleep and wake based on 90-minute sleep cycles
Enter your wake-up time and we'll calculate the best times to fall asleep.
Based on 90-minute sleep cycles. Waking at the end of a cycle means waking up naturally refreshed. Each row includes progressively fewer cycles.
Going to sleep now? We'll calculate the best times to wake up.
How much sleep do you owe your body?
Sleep occurs in 90-minute cycles made up of light sleep, deep sleep, and REM sleep. Waking up in the middle of a cycle — especially during deep sleep — causes that groggy, disoriented feeling (sleep inertia). Waking at the end of a complete cycle means you naturally surface at the lightest sleep stage and wake up feeling refreshed.
This is why sleeping 6 hours often feels better than 7: 6 is four complete cycles, while 7 may interrupt a fifth cycle partway through.