Children's BMI Calculator

BMI Calculator for Children and Teens

Body mass index (BMI) is one way to estimate a person's body fat. BMI is calculated using a person's weight and height. BMI is the most commonly used method to determine if an adult is overweight or obese. In children and teens, BMI is used to find out if a child is underweight, of a healthy weight, overweight, or obese. A child's body fat changes with age. Also, girls and boys differ in their amount of body fat as they mature. This is why BMI for children, also known as BMI-for-age, includes gender and age.

This calculator gives an approximate BMI for children from ages 5 to 18. It will tell you if a child is underweight, at an ideal weight, at risk of being overweight, or is now overweight.

Enter Child's Information


Centers for Disease Control and Prevention About BMI for Children and Teens

Centers for Disease Control and Prevention Growth Chart

Pietrobelli A., et al. "Body mass index as a measure of adiposity among children and adolescents: A validation study." Journal of Pediatrics. Vol. 132 no. 2. Feb. 1998.

Rosner, B. "Percentiles for body mass index in U. S. children 5 to 17 years of age." Journal of Pediatrics, Vol. 132 no. 2. Feb. 1998.

This calculator is not intended to replace the evaluation of a health care professional.