BMI (Body Mass Index) Calculator

Body Mass Index (BMI) is a guide for determining whether a person is underweight of normal weight or overweight based on their height and weight. Figure out your child's Body Mass Index (BMI) to determine if your child is at risk.

A child's body fatness changes as they grow and differs for boys and girls. Once you have calculated your child's BMI, view the charts below to determine if your child is overweight based on his or her gender and age.

BMI Calculator
Height: feet, inches or centimeters
Weight: pounds kilograms
Body Mass Index:

Using the CDC Growth Chart

Each of the BMI charts contains a series of curved lines indicating specific percentiles. The percentile curves show the pattern of growth for your child from preschool years into adulthood. BMI increases from early childhood into adulthood.

  1. To find your child's BMI-for-age percentile, first click on the gender specific chart below.
  2. Find your child's age on the horizontal scale (bottom of chart), and follow a vertical line to the BMI on the left.
  3. Place a dot where the child's age and BMI intersect.
Boys, 2 to 20 years Girls, 2 to 20 years

Understanding BMI-for-Age Percentiles


BMI-for-age > 85th precentile

If your child has a BMI-for-age that is equal to or higher than the 85th percentile, he or she is overweight. The majority of children who are overweight are also obese and need help with weight management. It is possible to be overweight without being obese, as is the case with athletes. It is important for children in this category to maintain a healthy diet and remain physically active. Annual screenings with a physician are important to monitor the child's weight in relation to his or her growth an development.


BMI-for-age > 95th percentile

Children with a BMI-for-age equal to or higher than the 95th percentile are considered obese. They are at higher risk for becoming obese adults and increased risk for chronic diseases later in life, including cardiovascular disease and diabetes. A physical exam with your child's physician is advised to determine the best course of action and rule out any potential medical conditions.

The data for the BMIs for overweight children aged 2-20 was adapted from the current guidelines as released by the Center for Disease Control's (CDC) National Center for Chronic Disease Prevention and Health Promotion.

Additional BMI Chart

Click here to view another example of a BMI chart. Adobe Acrobat
  • The area in red above the yellow shows the child's weight is considered obese for their age and height.
  • The area in yellow shows the child's weight is overweight for their age and height.
  • The area in green shows the child's weight is within the normal range for their age and height.
  • The area in red below the green shows the child's weight is considered underweight for their age and height.

Important: This information is not intended to substitute or replace the professional medical advice you receive from your child's physician. The content provided on this page is for informational purposes only, and was not designed to diagnose or treat a health problem or disease. Please consult your child's physician with any questions or concerns you may have regarding a medical condition.