Predict your child's adult height from the parents' heights, with the likely height range for a boy or a girl.
Last updated: November 7, 2026
The mid-parental (Tanner) method
This height calculator predicts how tall a child will be as an adult from the parents' heights, using the mid-parental (Tanner) method. Add the parents' heights, add 5 inches (13 cm) for a boy or subtract 5 inches (13 cm) for a girl, and divide by two. The 5 inches is roughly the average height difference between adult men and women. • Boy: (father + mother + 5 in) ÷ 2 • Girl: (father + mother − 5 in) ÷ 2 Example: father 5 ft 11 in (71 in), mother 5 ft 5 in (65 in). A boy: (71 + 65 + 5) ÷ 2 = 70.5 in, or 5 ft 10.5 in. A girl: (71 + 65 − 5) ÷ 2 = 65.5 in, or 5 ft 5.5 in. The result is an average, not a promise. About 95% of children end up within ±8.5 cm (about 3.4 in) of the prediction, which is the likely range the tool shows. Nutrition, health, the timing of puberty and the grandparents' genes all play a part. If you're worried about growth, ask a paediatrician and use real growth-chart measurements.
Common questions about predicting a child's height
Add the parents' heights, add 5 in (13 cm) for a boy or subtract 5 in (13 cm) for a girl, then divide by two.
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