Health
Sleep Calculator
🔒 Runs in your browser
Find the best wake-up times based on your bedtime and 90-minute sleep cycles. Free sleep calculator — no account required, runs in your browser.
Optimal wake-up times
4.5 hours (3 cycles)
02:45
6 hours (4 cycles)
04:15
7.5 hours (5 cycles)
Ideal05:45
9 hours (6 cycles)
Ideal07:15
Includes 15-minute sleep onset buffer. Waking between cycles helps you feel more rested.