# Predicting how tall your child will be

Is there a formula or some way of predicting how tall a child will be when he is fully developed?

Question:

## Robert Steele

Robert W. Steele, MD, is a board certified pediatrician at St. John's Regional Health Center in Springfield, MO. He graduated from medical... Read more

There are many "formulas" people have said are accurate in predicting how tall your child will be. Some say take the height at the second birthday and multiply it by two. Others have suggested simply adding the parents' heights and dividing by two. And still others have more elaborate schemes that take into account what month they were born in, the color of their eyes, and how tall they were at birth. (For more, check out our fetal growth chart.) But while some of these may have at one time been based upon some scientific ideas, most are only a reasonable guess at best.

Unfortunately, physicians can really do no better. We do know that genetic factors are of the greatest importance and influence the final adult height the most. And after having studied thousands of children and their parents, the following formula has been developed to assist in figuring out if growth is on track to reach that "genetic potential." The following equations are used by most endocrinologists to figure out the goal height in the children they are evaluating:

### FOR BOYS

1. Take each parent's height and add them together. If using the english system, total the number of inches. If using metric, add the centimeters together.
2. Divide that number by 2
3. Add 2.5 inches to that number if using the english system. Add 6.5 centimeters to the number if using metric.
4. This number is the midparental height for boys
5. This number plus or minus 4 inches (or plus/minus 10 centimeters) is the range in which you could expect your son to fall.

Example:

Mom is 5'4" (64 inches or 162.5 centimeters);
Dad is 6'1" (73 in. or 185.5 cm.)
Adding the two together = 137 in. or 348 cm.
Divide that by two = 68.5 in. or 174 cm
Add 2.5 in. or 6.5 cm. = 71 in. or 180.5 cm.
You could expect this boy to eventually be 5'11" plus or minus 4 in. or 180.5 cm. plus or minus 10 cm.

### FOR GIRLS

1. Take each parent's height and add them together. If using the english system, total the number of inches. If using metric, add the centimeters together.
2. Divide that number by 2
3. Subtract 2.5 inches to that number if using the english system Subtract 6.5 centimeters to the number if using metric
4. This number is the midparental height for girls
5. This number plus or minus 4 inches (or plus/minus 10 centimeters) is the range in which you could expect your daughter to fall.

Similar Example:

Mom is 5'4" (64 inches or 162.5 centimeters);
Dad is 6'1" (73 in. or 185.5 cm.)
Adding the two together = 137 in. or 348 cm.
Divide that by two = 68.5 in. or 174 cm.
Subtract 2.5 in. or 6.5 cm. = 66 in. or 167.5 cm.
You could expect this girl to eventually be 5'6" plus or minus 4 in. or 167.5 cm. plus or minus 10 cm.

I hope this helps.

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