Sleep Calculator – Find Your Best Time to Sleep
Calculate your ideal bedtime or wake-up time based on natural 90-minute sleep cycles
What Are Sleep Cycles?
Sleep cycles are natural 90-minute patterns your body goes through each night. Each cycle consists of four stages: light sleep, deep sleep, deeper sleep, and REM (rapid eye movement) sleep.
During a typical night, you experience 4-6 complete cycles. Waking up at the end of a cycle, rather than in the middle, helps you feel more refreshed and alert.
Why It Matters
Timing your sleep with your natural cycles can dramatically improve how you feel when you wake up. Even if you get the recommended 7-9 hours of sleep, waking up in the middle of a deep sleep cycle can leave you feeling groggy.
Our calculator helps you find the perfect bedtime or wake-up time, so you complete full sleep cycles and wake up during lighter sleep stages when it's easier and more natural to rise.
Frequently Asked Questions
Our calculator is based on the scientifically proven 90-minute sleep cycle. While individual cycles can vary slightly (between 80-120 minutes), 90 minutes is the average for most adults. The calculator provides excellent guidance, though you may need to adjust based on your personal experience.
Most adults need 5-6 complete sleep cycles per night, which equals 7.5-9 hours of sleep. However, some people function well on 4 cycles (6 hours), while others need 6 cycles (9 hours). Listen to your body and use this calculator to find your optimal amount.
If you're sleeping 8 hours but waking up tired, you might be interrupting your sleep cycles. 8 hours equals 5 cycles plus 30 minutes, which means you're waking mid-cycle. Try aiming for 7.5 hours (5 cycles) or 9 hours (6 cycles) instead.
Yes! Most people take 10-20 minutes to fall asleep. If you know it typically takes you 15-30 minutes to drift off, add that time to your calculation for more accurate results. This ensures you complete full sleep cycles.
Absolutely! If you want to adjust your sleep schedule, do it gradually. Shift your bedtime by 15-30 minutes every few days until you reach your target. Sudden changes can disrupt your body's natural rhythm and make it harder to adapt.