Childhood Obesity: Body Mass Index (BMI) Charts

Body Mass Index (BMI) is calculated from weight and height measurements and is used by your doctor to determine if your child's weight is appropriate for his or her height. BMI is a reliable measure of the amount of body fat for most children and teens.

Based on recommendations from the American Academy of Pediatrics, your pediatrician or family doctor will determine your child’s BMI at each routine checkup, starting when your child is 2 years old. Your doctor will plot the measurement on a BMI growth chart at each visit to see how your child compares to other children of the same age and gender and to determine if there are any changes over time.

For children, the BMI is used to screen for overweight, at risk of overweight, or underweight. It is important for parents to understand that the BMI is only a screening tool and does not diagnose a health problem. If your child’s BMI does not indicate a healthy weight, your child’s doctor may want to further evaluate your child to determine the cause.

Although BMI is a reliable indicator of body fat, it is not a perfect measure and there are situations where BMI may be misleading, or inaccurate. For example, BMI may be difficult to assess during puberty when kids are growing rapidly. In addition, a very muscular teen may have a high BMI since extra muscle adds to his or her body weight - but not fatness.

The best way to establish your child's BMI is to have your child's pediatrician perform and plot the measurements over time. That way, you'll know the numbers are accurate and your child's doctor can discuss the results with you.

If you're interested in learning more about BMI, visit the Body Mass Index home page on the CDC website: www.cdc.gov/nccdphp/dnpa/bmi/index.htm. The site provides a Child and Teen BMI Calculator, information about how to interpret the BMI percentile for children and teens, and access to nutrition and weight resources.