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Predicted adult height
The Tanner mid-parental height prediction used in clinical practice — plus the WHO height medians for context. The method gives a wide range, not a promise.
Growth charts and sleep ranges describe populations, not your child. The measurement that matters is the child's own growth curve, read by the child-health professional who knows the child. Anything worrying — stalled weight, breathing pauses in sleep, a measurement that jumped curve — is a reason to contact them, not to consult this page.
The calculator
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WHO height medians for context
| Age | Boys median | Girls median |
|---|---|---|
| birth | 49.9 cm | 49.1 cm |
| 1 month | 54.7 cm | 53.7 cm |
| 2 months | 58.4 cm | 57.1 cm |
| 3 months | 61.4 cm | 59.8 cm |
| 4 months | 63.9 cm | 62.1 cm |
| 5 months | 65.9 cm | 64.0 cm |
| 6 months | 67.6 cm | 65.7 cm |
| 9 months | 72.0 cm | 70.1 cm |
| 12 months | 75.7 cm | 74.0 cm |
| 18 months | 82.3 cm | 80.7 cm |
| 2 years | 87.1 cm | 85.7 cm |
| 3 years | 96.1 cm | 95.1 cm |
| 4 years | 103.3 cm | 102.7 cm |
| 5 years | 110.0 cm | 109.4 cm |
Sources: WHO Child Growth Standards · AASM consensus recommendations for sleep · checked 2026-09-03
Frequently asked questions
How is adult height predicted?
The Tanner method averages the parents' heights with a sex adjustment: for boys, (mother + father + 13) ÷ 2 cm; for girls, (mother + father − 13) ÷ 2 cm. The result is the centre of a range that spans roughly ± 8.5 cm in either direction.
How accurate is the prediction?
Useful, but wide: the ± 8.5 cm band means a predicted 178 cm boy can realistically land anywhere around 170-187 cm. It is a clinical ballpark, not a fortune.
Does nutrition or sleep change it?
They matter for reaching one's own genetic potential — that is what the growth curves track — but the mid-parental estimate is about the genetic starting point.
Track the years, not just the height
TempoLife keeps the family's routine in one place — the habits that help a child reach its own curve.