Calculate your optimal bedtime and wake-up time based on 90-minute sleep cycles to wake up feeling refreshed and energized
Discover the science behind sleep cycles and optimize your rest quality.
Our sleep calculator is designed around the science of sleep cycles to help you wake up feeling refreshed and energized. Here's how it works:
Select when you want to wake up, go to bed, or sleep right now. Our calculator works with any schedule.
We calculate optimal times based on 90-minute sleep cycles, ensuring you wake up at the end of a cycle rather than in the middle.
Most people need 15 minutes to fall asleep. Our calculator accounts for this "sleep onset" time automatically.
Sleep isn't just "time with your eyes closed" - it's a complex biological process that occurs in predictable cycles throughout the night.
Your body begins to relax and your brain waves slow down. Easy to wake up during this stage.
Physical restoration occurs. Growth hormone is released, and your immune system strengthens.
Dreams occur and memories are consolidated. Critical for mental health and cognitive function.
Waking up during deep sleep (stages 3-4) causes grogginess and sleep inertia. By timing your wake-up to the end of a complete cycle, you'll feel more alert and refreshed, even with the same total sleep time.
Our sleep calculator is based on the average 90-minute sleep cycle. During sleep, your brain goes through multiple cycles of light sleep, deep sleep, and REM sleep. Waking up at the end of a complete cycle (rather than in the middle) helps you feel more refreshed and less groggy.
A sleep cycle is the progression through the different stages of sleep, including light sleep, deep sleep, and REM sleep. Each complete cycle lasts approximately 90 minutes. Most adults go through 4-6 complete sleep cycles per night.
Most adults need 7-9 hours of sleep per night, which translates to 5-6 complete sleep cycles. However, individual needs may vary based on age, lifestyle, and health factors.
If you wake up in the middle of a sleep cycle, you might feel groggy regardless of total sleep time. This is called sleep inertia. Using our calculator to time your wake-up with the end of a sleep cycle can help you feel more refreshed.