Child Height Predictor Calculator
Estimate a child’s adult height from both parents’ heights using the mid-parental method. This is a broad family-height estimate, not a prediction of an individual child’s growth or a health assessment.
US inputs use total inches: 5 ft 5 in = 65 in. The range is a population guideline, not an individualized confidence interval.
How it’s calculated and sources
Average the parents’ heights, then add 6.5 cm for a boy or subtract 6.5 cm for a girl. The displayed range extends 10.2 cm on either side of that estimate. This page uses only parents’ heights; it does not use age, weight, bone age or the Khamis–Roche method.
Sources: Royal College of Paediatrics and Child Health: mid-parental formula; American Academy of Pediatrics: family target-height range. Source and implementation checked October 27, 2026.
Puberty timing, growth disorders and individual variation can affect adult height. An unusual growth pattern needs a pediatrician’s assessment using the child’s growth history. The adult BMI calculator is not a child-growth assessment.
Worked example
With a mother of 165.1 cm (65 in) and father of 177.8 cm (70 in), the parental average is 171.45 cm. Adding 6.5 cm for a boy gives 177.95 cm (about 5 ft 10 in), with a broad range of 167.75–188.15 cm.
Frequently asked questions
Does this track growth over time?
No. It estimates family adult-height potential from parents’ heights. Children’s growth should be assessed using age- and sex-specific growth charts with a pediatrician.
Does this use Khamis–Roche?
No. The earlier incomplete coefficient interpolation has been removed. This calculator consistently uses the mid-parental formula for both sexes.
How precise is the estimate?
The broad range is about four inches either side of the central estimate. It is not a guarantee and does not replace clinical assessment.