Sleep Calculator

A sleep cycle lasts approximately 90 minutes and includes light sleep, deep sleep, and REM sleep. Waking up at the end of a cycle helps you feel more alert and refreshed.

Most adults need 5-6 complete sleep cycles (7.5-9 hours) per night. Waking mid-cycle causes grogginess even after many hours of sleep.

Yes, the calculator adds about 15 minutes to account for the time it typically takes to fall asleep after lying down.