Stop waking up groggy. Use our calc to find the perfect bedtime based on your natural 90-minute sleep cycles.
To wake up feeling refreshed, aim for these times:
Note: The average human takes 14 minutes to fall asleep. The times shown above are when you should actually be asleep. We calculate this for you, so aim to be in bed by the times shown!
This calculator is based on the body's natural circadian rhythms and sleep cycles. A typical sleep cycle lasts about 90 minutes.
If you wake up in the middle of a sleep cycle (during deep sleep), you will likely feel groggy and disoriented—a feeling known as sleep inertia. Waking up at the end of a cycle ensures you wake up during light sleep, feeling refreshed and alert.
Your body relaxes, heart rate slows. Easy to wake up.
Critical for physical restoration. Waking up now is difficult and painful.
Brain activity increases. Essential for memory and learning.
