Free sleep calculator. Find the best bedtimes and wake-up times based on 90-minute sleep cycles for maximum energy and focus.
☝️ These bedtimes are based on 90-minute sleep cycles. Waking between cycles helps you feel more refreshed.
A blackout eye mask, white noise machine, or memory foam pillow can transform your sleep cycles.
A typical sleep cycle lasts approximately 90 minutes and includes light sleep, deep sleep, and REM (rapid eye movement) sleep. Adults need 5–6 complete cycles per night (7.5–9 hours) for optimal health and cognitive performance.
Waking up in the middle of a deep sleep stage causes "sleep inertia" — that groggy, disoriented feeling. By timing your alarm to coincide with the end of a sleep cycle, you wake during lighter sleep, feeling more alert and refreshed.