How to Predict a Child's Adult Height

It's impossible to predict with absolute certainty just how tall your youngster will grow. The most accurate method of height prediction is the Bone-Age method, but this procedure requires an X-ray of the child. Fortunately, there are a variety of ways to make a reasonably educated guess with just a few simple measurements.

Adult Height Variables

A child’s adult height is the result of a combination of influences, including genetic predispositions, gender, nutrition, environment and health status. However, the height of a child’s parents generally is the best way to predict adult height, according to Harvard Medical School's Harvard Health Publications 3. Boys often reach a height similar to their fathers, while girls often reach adulthood approximately the same height as their mothers.

Parent Height Indicators

You can use your height and the height of your partner as a guide to your youngster’s adult height. For a female child, subtract 5 inches (13 centimeters) from the father's height, explains the American Academy of Family Physicians 1. Add this number to the mother's height and divide by 2. The result is a prediction of adult height.

For a male child, add 5 inches (13 centimeters) to the mother's height. Add this number to the father's height and divide by 2 for the result. This mid-parental method of height prediction is generally accurate with 2 to 3 inches, states the Family Practice Notebook website 2.

Child Height Calculations

You can estimate adult height, even when your child is a toddler, according to Dr. Wolens of the VIP Pediatrics website. For boys, use the height measurement in centimeters at 3 years of age, multiply it by 1.29 and add 54.9 centimeters. For girls, multiply the height at age 3 by 1.29 and then add 42.3 cm. To convert the result to inches, multiply it by 0.3937.

Adult height can also be predicted in older children and teens between the ages of 8 and 16. A combination of gender, age, height, sitting height and weight are used in the complex calculation, according to the University of Saskatchewan's College of Kinesiology website, where an online calculator simplifies the formula.

Khamis-Roche Method

The Khamis-Roche method is a reasonably accurate predictor of a child's adult height. In fact, it generally predicts a child’s adult height within 1 1/2 inches. This method uses the child's age and gender, his current height and weight, his mother's height and his father's height, as well as coefficients for individual age derived from a table of regression coefficients. The equation can only be used to estimate adult height in children between 4 and 17 years of age, and was created based upon research of Caucasian-American subjects. You can find calculators online for simple computations. The equation for the Khamis-Roche method of height prediction equals: Child’s height (multiplied by a coefficient) + child’s weight (multiplied by a coefficient) + midparents height (multiplied by a coefficient) (multiplied by a coefficient)

For example, the equation for height prediction in a 10-year-old boy: 137.16 cm (0.996) + 70 pounds (-0.379) + 175.26 cm (0.312) (-0.255)

Predicted Height = approximately 177.8 centimeters which is 70 inches or 5 foot 10 inches tall.