Body mass index (BMI) is a measure of body fat based on height and weight that applies to both males and females. To use the BMI calculator:
Child BMI Categories are based on the BMI percentile, which varies with gender and age. You can calculate the BMI percentile using the CDC Calculator or a chart (Boys/Girls; Niños/Niñas). For example, a 10-year-old boy with a BMI of 23 (a 'normal' BMI for an adult) is above the 95th percentile and obese for his age.