Child and Teen BMI
Body Mass Index (BMI) is a number calculated from a child's weight and height. BMI is an inexpensive, easy, and fairly reliable indicator of body fatness for most children and teens. BMI does not measure body fat directly, but can be considered an alternative for direct measures of body fat. For children and teens, BMI is age and sex-specific and is often referred to as BMI-for-age.
After BMI is calculated for children and teens, the BMI number is plotted on the CDC BMI-for-age growth charts (for either girls or boys) to obtain a percentile ranking. Percentiles are the most commonly used indicator to assess the size and growth patterns of individual children in the United States. The percentile indicates the relative position of the child's BMI number among children of the same sex and age. The growth charts show the weight status categories used with children and teens (underweight, healthy weight, overweight, and obese).