Height Calculator

What is a height calculator?

A height calculator estimates how tall a child is likely to be as an adult, based on the heights of their two biological parents. It uses the mid-parental height method (also called the Tanner method), a simple rule long used by pediatricians as a quick guide. The result is a prediction, not a guarantee — it gives a likely adult height and a range around it, because children of the same parents can still end up shorter or taller.

How adult height is predicted

First, add the two parents' heights together. For a boy, add 13 cm (about 5 inches) before halving; for a girl, subtract 13 cm before halving. The 13 cm reflects the average adult height difference between men and women.

• Boy: predicted height = (father's height + mother's height + 13) ÷ 2
• Girl: predicted height = (father's height + mother's height − 13) ÷ 2

Most children end up within about 10 cm (4 inches) either side of this figure, so the calculator shows that target range too.

Worked example

If the father is 180 cm and the mother is 165 cm and the child is a boy: (180 + 165 + 13) ÷ 2 = 179.0 cm, with a likely range of about 169 to 189 cm. For a girl with the same parents: (180 + 165 − 13) ÷ 2 = 166.0 cm, range about 156 to 176 cm.

What the result means

Think of the number as the middle of a likely range, not an exact destiny. Genetics is the biggest driver of height, but nutrition, sleep, general health and overall growth all play a part. A child's own growth curve, tracked over time by a doctor, is a more reliable guide than any single prediction. This tool is for general interest and education only and is not medical advice.

Pair this with our BMI Calculator, Ideal Weight Calculator and Due Date Calculator, or browse all health calculators.