Body mass index (BMI) is weight compared to height. The healthy BMI range is the same for all people 18 and older, while healthy ranges vary for children. Because your child is still growing, your pediatrician compares your child’s BMI to the healthy BMI of children of the same gender and age, placing your child into a BMI percentile. Children should fall between the 5th and 85th BMI percentile.

BMI is a barometer for your child’s growth, and is an important tool for you and your pediatrician to detect whether your child may be either overweight or underweight.

If your child is two and older, every time they visit the pediatrician, the pediatrician should check their BMI to ensure that it’s in the normal range. You can also calculate your child's BMI and consult your pediatrician if you have concerns about your child’s development.