How to calculate how tall your child will grow up to be? It’s pretty easy to calculate, add mother’s height to the father’s height in either inches or centimeters. But remember these calculations are just estimates but fun to do!👯‍♀️Method 1 Add 5 inches (13 centimeters) for boys or subtract 5 inches (13 centimeters) for girls.Divide by 2.👯‍♀️Method 2 Another way to estimate a child’s adult height is to double a boy’s height at age 2 or a girl’s height at age 18 monthsIt’s also important to no