Calculator Methodology

The NappyTi.me sleep calculator subtracts 90-minute cycles plus a configurable 15-minute sleep onset buffer from your target wake time. Cycle length is adjusted for age group based on sleep research consensus.

Adult formula

Bedtime options = wakeTime − (cycles × 90 min) − 15 min onset. We return three options corresponding to 6, 5, and 4 complete cycles.

Age adjustments

Newborns: ~50-min cycles, 14–17 hours total. Toddlers: 60-min cycles, 11–14 hours. School-age: 80-min cycles, 9–11 hours. Adults: 90-min cycles, 7–9 hours. Seniors: variable, 7–8 hours.

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