Height calculator: how tall will you be?
Enter a child’s age, height and both parents’ heights. You get the mid-parental estimate, a Khamis-Roche prediction when you add a weight, and their place on the CDC growth chart.
How this calculator works
It runs three standard methods and shows you each one, so you can see where the number comes from.
Mid-parental height. The average of both parents, shifted up 6.5 cm for boys and down 6.5 cm for girls. It needs nothing but the parents’ heights, which also makes it the least precise.
Khamis-Roche. Adds the child’s own height and weight to the parents’ average, weighted differently at each age. It is the most accurate method that does not need an X-ray, and it is the headline number whenever you enter a weight for a child aged 8 to 17.
CDC growth chart. Shows which percentile the child is on today. Healthy children tend to follow their percentile line, so the chart doubles as a sanity check on the prediction.
What a prediction cannot tell you
Every method here assumes average puberty timing. A child who starts puberty early is tall for their age now and stops sooner; a late bloomer is the reverse. If height has crossed two percentile lines, or growth has stalled for a year, that is worth a visit to a pediatrician. For the timing side, try the growth plate calculator.
Frequently asked questions
How accurate is a height calculator?
For a healthy child, the mid-parental formula is usually within about 8.5 cm (3.3 in) of the real adult height. The Khamis-Roche method, which also uses the child’s current height and weight, is tighter: most predictions land within about 5 cm (2 in). Neither can see puberty timing, so an early or late bloomer can end up outside the range.
What is the mid-parental height formula?
Add the mother’s and father’s heights, add 13 cm (5 in) for a boy or subtract 13 cm for a girl, then divide by two. The result is the target height, and most children finish within 8.5 cm either side of it.
What is the Khamis-Roche method?
A prediction published in the journal Pediatrics in 1994. It combines a child’s current height, current weight and the average of the parents’ heights using age-specific weights, and it does not need a bone-age X-ray. It applies from age 4 to 17.5 and was developed on healthy white American children, so it is less reliable outside that group.
What does my height percentile mean?
It is where you stand among 100 children of the same age and sex on the CDC growth chart. The 60th percentile means you are taller than about 60 of them. Children usually track along the same percentile line as they grow, which is why the chart can project an adult height.
Can I grow taller than the calculator predicts?
Yes. The prediction is the middle of a range, not a ceiling. Genetics set most of the range, and sleep, nutrition, activity and overall health influence where in it you finish. No exercise or supplement can add height beyond your genetic range or after growth plates close.
At what age do you stop growing?
Most girls reach adult height around 14 to 16 and most boys around 16 to 18. Late bloomers can keep growing into their late teens.