Estimate only. Growth also depends on nutrition, health and many genes. Not medical advice.
This height predictor estimates a child’s adult height from the heights of both parents using the mid-parental height formula, the same rule pediatricians use as a first guess. Enter the mother’s and father’s heights, choose boy or girl, and the tool shows the predicted adult height, the ±10 cm target range and the formula it used. Switch between centimetres and feet and inches at any time; the values you typed are converted for you.
Adult men are on average about 13 cm taller than adult women, so the parents’ heights first have to be put on the child’s own scale. For a boy, add the two heights, add 13 cm and divide by 2. For a girl, add the two heights, subtract 13 cm and divide by 2. In imperial units the correction is 5 inches. The result is the child’s expected adult height, and roughly two thirds of children finish within 10 cm (4 inches) above or below it, which is the range drawn under the number.
A mother of 165 cm and a father of 178 cm add up to 343 cm. For a son the calculator computes (165 + 178 + 13) ÷ 2 = 178 cm and shows a range of 168 to 188 cm. For a daughter it computes (165 + 178 − 13) ÷ 2 = 165 cm, with a range of 155 to 175 cm. In feet and inches the same parents are 5’5” and 5’10”, giving 5’10” for a boy and 5’5” for a girl.
Height is one of the most heritable human traits, but it is controlled by thousands of genetic variants of small effect rather than a single gene, which is why no Punnett square can draw it. Nutrition, sleep, chronic illness and the timing of puberty all move the outcome. The mid-parental estimate captures the family average, not the individual child, so use it as a reference point and rely on a growth chart from regular check-ups for a real forecast. For traits that do follow a few alleles, the eye color and blood type calculators show the Punnett square approach.
Add both parents' heights in centimetres. For a boy add 13 cm and halve the total; for a girl subtract 13 cm and halve it. In inches use 5 instead of 13. The calculator shows the formula under the result.
The mid-parental method is a population average, so the estimate comes with a target range of about ±10 cm (4 inches). Most children end up inside that range, but individual results can fall outside it.
Because adult men are on average about 13 cm (5 in) taller than adult women. Adding or subtracting half that difference twice converts the parents' heights to the child's sex.
Yes. Height is polygenic and depends on nutrition and health during growth, so children regularly land at the top of the range or beyond it, especially when one parent is much taller than the other.
Girls usually finish growing at 14 to 16, boys at 16 to 18, after the growth spurt of puberty. A pediatrician's growth chart or a bone-age x-ray gives a better forecast for an individual child than any formula.