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CalcHub Blog
March 26, 20263 min read

Child Height Predictor Calculator: Estimate Your Child's Adult Height

Predict your child's adult height using parent heights, current height, and bone age methods. See height predictions with a realistic range of outcomes.

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"Is he going to be tall?" Every parent of a long-legged toddler hears this question. While no calculator is a crystal ball, the CalcHub Child Height Predictor uses well-validated formulas to estimate your child's adult height — and more usefully, gives you a realistic range rather than a false single number.

The Mid-Parental Height Method

The most commonly used method — and the one most pediatricians reference — uses parents' heights to estimate the child's genetic potential:

For boys: (Mother's height + Father's height + 13 cm) ÷ 2 For girls: (Mother's height + Father's height - 13 cm) ÷ 2

Then add ±10 cm for the typical range. So if both parents are 170 cm (5'7"), a son's predicted height would be:

(170 + 170 + 13) ÷ 2 = 176.5 cm, range: 166.5 – 186.5 cm

That's a pretty wide range — which is honest, because genetics isn't destiny and other factors matter too.

The Khamis-Roche Method

More precise for children with known current measurements. Uses the child's current height, weight, and age along with parent heights to refine the prediction. The calculator applies this formula when you enter your child's current measurements.

Child AgePrediction Accuracy (Khamis-Roche)
Under 2 yearsLess reliable — too early
4–6 years±7 cm typical range
8–10 years±5 cm typical range
12–14 years±3–4 cm typical range
Post-puberty±1–2 cm

Bone Age vs. Chronological Age

The most precise method for height prediction requires an X-ray of the child's left hand and wrist to determine "bone age" — how mature the growth plates are. A child whose bone age is 2 years behind their chronological age will likely grow for longer than average.

This isn't something the calculator can determine on its own, but if your pediatrician has ordered a bone age X-ray, you can enter the result for a more accurate prediction.

Factors That Affect Final Height

Genetics is the biggest factor, but not the only one:


  • Nutrition: Chronic malnutrition in childhood reduces height potential

  • Sleep: Growth hormone is primarily released during deep sleep

  • Exercise: Moderate activity supports normal bone development; excessive running/gymnastics in early childhood may (rarely) affect it

  • Medical conditions: Some hormonal and chronic conditions affect growth


The calculator focuses on the genetic component — your pediatrician handles the rest.

My child is much taller/shorter than predicted. What does that mean?

The predicted range accounts for most genetic variation, but outliers exist. A child consistently below the predicted range despite good nutrition and health deserves a conversation with their pediatrician about growth hormone levels or other factors.

At what age does height growth stop?

Girls typically stop growing about 2 years after their first period, usually by age 16–17. Boys often continue growing until 18–21. Growth plates close later in boys, which is why men average about 13 cm taller than women despite similar genetics.

Can I improve my child's height?

You can't override genetics, but you can ensure they reach their genetic potential: adequate protein and calcium, sufficient sleep, and avoiding chronic stress or undernutrition.

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