🌙 Calculate Your Sleep Times
Find the perfect bedtime or wake-up time based on 90-minute sleep cycles. Wake up feeling refreshed, not groggy.
Sleep occurs in 90-minute cycles consisting of light sleep, deep sleep, and REM (rapid eye movement) sleep. Waking up at the end of a complete cycle — rather than in the middle of deep sleep — is what makes the difference between feeling refreshed and feeling groggy. Our sleep calculator finds the optimal times to wake up or go to bed so you complete full cycles.
Adults need 7-9 hours of sleep per night, which equals 5-6 complete 90-minute cycles. Teenagers need 8-10 hours, and younger children need even more. Consistently getting fewer than 7 hours increases the risk of obesity, diabetes, heart disease, and impaired cognitive function.
Keep a consistent sleep schedule — wake up at the same time every day, even on weekends. Avoid screens for 30-60 minutes before bed, as blue light suppresses melatonin production. Keep your bedroom cool, dark, and quiet. Avoid caffeine after 2pm. Regular exercise improves sleep quality but avoid vigorous workouts within 2 hours of bedtime.