Sleep Calculator

Bedtimes for a target wake time using 90-min cycles.

Wake-up time

For 6 cycles (9h)21:45

For 5 cycles (7.5h)23:15

For 4 cycles (6h)00:45

Includes ~15 min to fall asleep; each cycle ≈ 90 min.

Ad space (in-content)

Formula / method used

Bedtime = wake − cycles×90min − 15min.