The Sleep Cycle Calculator is a free tool designed to help you find the ideal time to go to bed or wake up based on 90-minute sleep cycles, the natural rhythm of human sleep.
Our goal is to help you wake up feeling rested by aligning your alarm with the end of a sleep cycle, when you're in light sleep rather than deep sleep.
This website is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. The information provided should not replace consultation with a qualified healthcare professional.
If you experience persistent sleep problems, please consult a doctor or sleep specialist.
Sleep calculations are based on average 90-minute cycles. Individual cycles may vary between 80-120 minutes depending on age, health, and other factors.