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װײַז די װײַז־פּראָגראַם

A sleep cycle calculator picks the best times to fall asleep or wake up so you rise at the end of a 90-minute cycle rather than the groggy middle. Sleep runs in these cycles of roughly 90 minutes, and this tool works backward from a wake-up time to suggest bedtimes, or forward from a bedtime to suggest wake times, targeting complete 5–6 cycle nights and allowing time to fall asleep. Times can be shown in 24-hour or 12-hour format.

Choose whether you know your wake-up time or your bedtime, then the tool steps in 90-minute cycles from that anchor and lists the times that complete a whole number of cycles. It also adds a buffer (15 minutes by default) for the time it takes to actually drift off, so the cycle clock starts when you fall asleep, not when you get into bed. It highlights the 5- and 6-cycle options — about 7.5 to 9 hours — as the best targets.

For example, to wake at 7:00 am with a 15-minute fall-asleep buffer, good bedtimes are about 9:45 pm (6 cycles) or 11:15 pm (5 cycles), because each leaves you finishing a cycle right at 7:00 am. Working the other way, going to bed at 11:00 pm points to waking near 6:30 am or 8:00 am. Use it to plan a bedtime for an early alarm, or to pick a wake time that avoids the groggy feeling of waking mid-cycle.