Find the perfect time to go to bed or wake up based on natural sleep cycles
Select whether you want to calculate bedtime or wake-up time, enter your preferred time, and click calculate. The results will show optimal times based on 90-minute sleep cycles.
Sleep isn't just about quantity—it's about quality. Understanding sleep cycles can help you wake up feeling more refreshed, even if you sleep fewer hours.
A sleep cycle lasts about 90 minutes and consists of four stages: NREM 1, NREM 2, NREM 3 (deep sleep), and REM sleep. Completing full cycles is key to waking up refreshed.
Most adults need 7-9 hours of sleep per night, which equals 5-6 complete sleep cycles. The exact amount varies by individual.
The best time depends on your natural circadian rhythm and schedule. Most people sleep best between 10 PM and midnight and wake between 6 AM and 8 AM. Our calculator helps find times that align with your sleep cycles.
Most adults need 7-9 hours of sleep per night. Teenagers need 8-10 hours, and younger children need 9-12 hours. However, sleep quality matters as much as quantity.
Waking during deep sleep stages can cause sleep inertia—that groggy, disoriented feeling. This is why our calculator recommends wake times that align with the end of sleep cycles.
For most people, 6 hours is insufficient for optimal health and cognitive function. While some people may function on 6 hours, long-term sleep deprivation has serious health consequences.
Our calculator is based on the scientific understanding of 90-minute sleep cycles. However, individual sleep patterns can vary. Use it as a guide and adjust based on how you feel.