Sleep Calculator
Calculate optimal sleep and wake times based on 90-minute sleep cycles. Free online sleep calculator.
03:452 cycles (3 hrs)
02:153 cycles (4.5 hrs)
00:454 cycles (6 hrs)
23:155 cycles (7.5 hrs)
21:456 cycles (9 hrs)
Based on 90-min sleep cycles + 15 min to fall asleep.