Ketsia Olangi — Sleep Hours by Age | ketsia-olangi.com
Take the hours from your age row, split them into 90-minute cycles, pick a wake time, and count whole cycles back to a bedtime.
Start with the hours your age row recommends. Adults 18–64 fall between seven and nine hours, which corresponds to four, five or six cycles of 90 minutes: six hours, seven and a half hours, and nine hours respectively.
Next, pick a fixed wake time. The wake time is the anchor because it is usually set by obligations, while the bedtime is the variable you are free to move.
Count whole cycles backwards from the wake time. Five cycles before 07:00 gives a bedtime of 23:30; six cycles gives 22:00; four cycles gives 01:00. Whole cycles only — waking partway through a cycle removes most of one stage rather than half of it.
On narrow screens, swipe or scroll the plate sideways.
For children, keep a consistent bedtime routine night after night. The routine signals the transition and supports falling asleep quickly, which feeds the quality half of the measure alongside duration.
At the end of the week, check whether the sleep was unbroken rather than only long. Duration measures length of sleep; quality covers how fast you fell asleep and whether the night stayed whole.
The failure mode to watch for is cutting below the lower bound of the range: under seven hours for adults, under eight for teenagers, under nine for school-age children. Below that line the schedule is short by the table's own standard.
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