Dietitians of Canada

BMI Calculator For Children and Teens

Body Mass Index for children ages 2 to 19

Determining a child’s BMI is a little different than for adults. BMI graphs are used because children are still growing and the amount of body fat changes as they grow. Plus, there are different charts based on gender, since body fat levels are different in boys and girls.

To learn more about the BMI results, talk to your child’s doctor. You can also find out more about what your child’s BMI means by following these steps:

1. Click on the correct BMI graph that matches your child’s gender (e.g. click on “Girls BMI 2-19 years” if your child is a girl)
2. Download a copy of the BMI chart onto your computer
3. To determine your child’s percentile for their weight category (underweight, healthy weight, overweight or obese), you’ll need to plot your child’s BMI onto the chart using these steps:
   • Find their BMI number on the vertical axis (the line running on the side of the chart)
   • Find their age on the horizontal axis (the line along the bottom of the chart)
   • Locate the point on the chart where the “BMI” and “age” meet. This is your child’s percentile.
4. Determine your child’s weight category based on their percentile by using the charts below:

• 

  BMI 2-19 Girls –
  click here to enlarge

• 

  BMI 2-19 Boys –
  click here to enlarge

For children aged 2 – 5:

For children aged 5 to 19:

What should I do if my child’s BMI is not within the healthy weight range?

Speak with your child’s doctor if you are concerned about the results. For information on healthy eating, talk to a registered dietitian. Find a registered dietitian in your area.
Learn more