How adult height is predicted
The mid-parental method estimates a child's adult height from the parents': for a boy, (father + mother + 13 cm) ÷ 2; for a girl, (father + mother − 13 cm) ÷ 2. The 13 cm reflects the average adult height difference between sexes. Most children land within about 8.5 cm either side of the estimate. Once a child's adult height is estimated, a matching reference weight comes from the ideal weight calculator.
How to use this calculator
Enter the mother's and father's heights in centimetres and the child's sex (1 for boy, 0 for girl). The result shows the predicted adult height and a likely range. It's a rough genetic estimate, not a guarantee. If your measurements are metric, convert them first with the cm to inches calculator.
What else affects height
Genetics set the broad range, but nutrition, sleep, general health and hormones during growth also matter. Children follow growth percentiles over time; a paediatrician's growth chart is far more reliable than any single prediction. This tool is for general information only, not medical advice. Height is also the main input to the BMI calculator.
Frequently asked questions
- How do I predict my child's adult height?
- Use the mid-parental method: for a boy, add the parents' heights plus 13 cm and divide by 2; for a girl, subtract 13 cm instead. Expect a range of about ±8.5 cm.
- How accurate is the mid-parental method?
- It gives a reasonable midpoint, but actual adult height commonly varies by several centimetres because of nutrition, health and individual genetics.
- Can a child be taller than both parents?
- Yes. The estimate is an average; individual genetics, nutrition and health can put a child above or below the parents' range.
- Does this work for adults?
- No. It predicts a child's future adult height from the parents' heights; it doesn't apply once growth is complete.
- What if I only know the parents' heights in feet and inches?
- Convert to centimetres first by multiplying total inches by 2.54, so 5 ft 10 in becomes 178 cm. Entering feet or inches directly produces a nonsense prediction, because the 13 cm adjustment assumes metric input.