BMI in children and teens
BMI can be calculated the same way for children and teens as it is for adults, but the numbers don’t have the same meaning. This is because the normal amount of body fat changes with age in children and teens, and is different between boys and girls. So for kids, BMI levels that define being normal weight or overweight are based on the child’s age and gender.
To account for this, the US Centers for Disease Control and Prevention (CDC) has developed age- and gender-specific growth charts. These charts are used to translate a BMI number into a percentile based on a child’s sex and age. The percentiles are then used to determine the different weight groups:
- Underweight: less than the 5th percentile
- Normal weight: 5th percentile to less than the 85th percentile
- Overweight: 85th percentile to less than the 95th percentile
- Obese: 95th percentile or higher
An easy way to determine your child’s BMI percentile is to use the CDC’s online BMI percentile calculator at http://apps.nccd.cdc.gov/dnpabmi.
Even in a young person, being overweight or obese can cause health problems. And it may directly increase the risk for certain health problems later in life, including some kinds of cancer. It also increases the chances of being overweight or obese as an adult, as well as the risk of health problems that can come with this.
Last Medical Review: 01/30/2013
Last Revised: 01/30/2013