How to Use the Child Height Predictor

Enter both parents' heights and select the child's sex to get a statistical prediction of their adult height. This calculator uses the widely cited mid-parental height formula: for boys, (mother's height + father's height + 13 cm) ÷ 2; for girls, (mother's height + father's height − 13 cm) ÷ 2. The 13 cm adjustment accounts for the average height difference between adult men and women.

Example

For a mother who is 163 cm and a father who is 178 cm, a son's predicted adult height is (163 + 178 + 13) ÷ 2 = 177 cm, while a daughter's predicted adult height is (163 + 178 − 13) ÷ 2 = 164 cm. Both estimates carry a typical margin of error of roughly ±10 cm either way.

Common Use Cases

FAQs

How accurate is the mid-parental height formula?

This is a statistical estimate, not a guarantee — the typical margin of error is roughly ±10 cm (about ±4 inches) around the predicted value, meaning the true adult height usually falls somewhere within that wider range rather than landing exactly on the single predicted number. The formula captures the general genetic tendency toward parental height but cannot account for individual genetics, nutrition, childhood illness, hormonal factors, or overall health during growth years — all of which can meaningfully shift a child's actual adult height above or below this estimate.

What is the 13 cm adjustment for?

It corrects for the average height gap between adult men and women (roughly 13 cm), so the formula adds it for boys and subtracts it for girls before averaging both parents' heights.

Should I use this instead of a pediatrician's growth chart?

No — this tool is for general interest and rough estimation only. A pediatrician tracks your child's actual growth against standardized growth charts over time, which is a far more reliable way to monitor healthy development than a one-time genetic estimate like this.