Child Height Predictor
How tall your child is likely to be as an adult, from the parents’ heights.
Good to know. Tall parents tend to have children a little shorter than themselves, and short parents a little taller.
Not medical advice. A general estimate for healthy adults.
How it works
In plain words
Add the parents’ heights. For a boy, add 13 cm (5 inches); for a girl, take 13 cm away. Divide by 2. Most children end up within about 10 cm (4 inches) of that.
The formula
boy = (mother + father + 13 cm) ÷ 2 girl = (mother + father − 13 cm) ÷ 2 range ≈ ± 10 cm (± 4 in)
Worked example
With a mother of 165 cm and a father of 180 cm, a boy’s mid-parental height is (165 + 180 + 13) ÷ 2 = 179 cm, and most boys of such parents end up between 169 and 189 cm.
Sources
- Mayo Clinic, Child growth: Can you predict adult height? Add 5 inches (13 cm) for a boy or subtract them for a girl, then average; most children are within about 4 inches (10 cm).
Sources checked October 3, 2026. 3 automated tests check its answers on every change.
About the child height predictor
Height runs strongly in families, and doctors use a simple estimate called the mid-parental height. It averages the parents’ heights after adjusting for the difference between men and women, about 13 cm (5 inches): a boy gets half of it added, a girl half of it taken away.
It is an estimate, not a forecast. Most children end up within about 10 cm (4 inches) of it, but some fall outside, and siblings can differ by as much. Nutrition, health and sleep in childhood matter, and so does chance: the genes for height are many, and each child gets a different mix.
Doctors use it mainly as a check. A child growing steadily along a line on the growth chart that leads near the mid-parental height is usually growing as expected. A child whose growth curve crosses lines, or who is far from the family pattern, is worth a doctor’s look. More precise predictions use a hand X-ray to see how much growing is left.
Measure both parents without shoes, rather than going by the height on a licence. For a child’s age, use the age calculator; to convert heights, the height converter.
Questions people ask
How can I predict my child’s adult height?
Add the parents’ heights, add 13 cm for a boy or subtract 13 cm for a girl, and divide by 2. Most children end up within about 10 cm of that.
How accurate is the mid-parental height?
It is a rough guide: most children land within about 10 cm (4 inches) of it, and some further away.
Can a child be taller than both parents?
Yes. The prediction is an average, and children often end up taller or shorter than the formula suggests.