Calculate the ideal bedtime or wake-up time based on 90-minute sleep cycles for optimal rest.
Enter your values below
Choose whether you're setting a wake time or bedtime.
Enter the time in 24-hour format (e.g., 07:00).
Most adults need 5 cycles (7.5 hours) per night.
How this calculator works
Sleep occurs in 90-minute cycles. Waking at the end of a cycle (after stages 1-5) leads to feeling refreshed. This calculator subtracts the number of cycles × 90 minutes plus ~14 minutes to fall asleep from your desired wake time.
Common questions about this calculator
Persistent sleep problems may indicate a sleep disorder. Consult a sleep specialist if you consistently have difficulty sleeping.
