Measuring Weight in Children and Adolescents

Measuring Weight Status in Children

Obesity in children is determined by using a method called “BMI-for-age percentiles.” BMI stands for Body Mass Index, which is a way to see if your child’s weight is appropriate for their age and height.

Here’s how you can find your child’s BMI-for-age percentile:

1. First, calculate your child’s BMI using their weight and height. Click here to use a BMI chart for children that shows weights and heights.
2. Once you have the BMI number, find your child’s age on the bottom of the BMI-for-age percentile chart (click here for boys and here for girls), then look to the left or right to find their BMI.
3. Use a pen or pencil to mark the point on the chart where their BMI and age meet. Find the shaded color on the bottom of the chart that matches the point you marked. This will show your child’s BMI-for-age percentile.
4. To determine your child’s weight status, check the table located to the right of the chart.

Useful Links:

• BMI Chart
• Girls BMI-for-Age Percentile Chart
• Boys BMI-for-Age Percentile Chart

A Note about BMI and Age Percentiles: 

Remember, BMI-for-age percentile is just one way to check to see if your child is at a healthy weight. Despite its widespread use, BMI has limitations. It doesn’t directly measure body fat or consider things like muscle mass and bone mass. For example, shorter children with a muscular build may have a high BMI but little body fat. Athletes may have a high BMI due to having higher muscle mass. Social determinants and race can also play a role in a child’s BMI.

Generally, if your child’s BMI-for-age percentile is higher than 95%, it could mean they have too much body fat and might be at risk for health complications. Always talk to a qualified health professional to get advice about your child’s weight and health.

If your child’s BMI is not listed on the charts above, please click here to calculate their BMI.

*Disclaimer: You cannot measure a child’s weight using solely BMI. You must calculate their BMI and then plot it on the BMI-for-age percentile chart to determine their weight status.*

To learn more about childhood obesity, click here.

Please note: The body mass index (weight in kg/height in meters²) is used to screen for obesity, but it does not displace clinical judgment. BMI is not a measure of body fat. Social determinants, race, ethnicity, and age may modify the risk associated with a given BMI. Please talk with your healthcare provider about understanding BMI.