Child Height Predictor
Predict a child's adult height from the parents' heights and the child's current growth percentile.
About the Child Height Predictor
Enter the child's sex and both parents' heights, and optionally the child's age and current height. The calculator gives the mid-parental target with a likely range, and the height the child's current percentile leads to.
The mid-parental height method (Tanner) averages the parents' heights and adds 6.5 cm for boys or subtracts 6.5 cm for girls; most children end within about ±8.5 cm of this target. If you add the child's current height, the calculator also projects the CDC height percentile they're following to age 20. Puberty timing can shift the result.
The formula
Boys: (father + mother + 13 cm) ÷ 2; girls: (father + mother − 13 cm) ÷ 2
Worked example
A girl whose mother is 5 ft 4.5 in and father 5 ft 10 in
- Average of the parents minus 6.5 cm (about 2.6 in)
- Target about 5 ft 4.7 in
- Likely range about 5 ft 1.3 in to 5 ft 8 in
Questions people ask
How accurate is it?
A guide only; genetics, nutrition, health and puberty timing all matter.
Can a doctor predict better?
A bone-age X-ray can refine predictions.