Body Mass Index for Kids

Body Mass Index, or BMI, is a number that doctors calculate using your height and weight. For kids, BMI is compared to other kids of the same age and sex. It helps doctors check if you are growing in a healthy way.

How BMI Works for Kids

A doctor measures your height and weight and uses those numbers to find your BMI. Then they compare your BMI to a chart of other kids your age. This shows if your weight is in a healthy range.

Kids' BMI changes as they grow. What is normal for an eight-year-old is different from what is normal for a twelve-year-old.

BMI Is Just One Tool

BMI does not tell the whole story. A very muscular kid might have a high BMI even though they are healthy. BMI does not measure body fat directly.

Doctors use BMI along with other information to check your health. The most important things are eating well, staying active, and feeling good.

Fun Facts

• BMI was invented by a Belgian mathematician in the 1830s.
• Doctors use special growth charts just for kids because children are still growing.
• Muscle weighs more than fat, which is why BMI is just one piece of the puzzle.

Did You Know?

There are different BMI charts for boys and girls because they grow and develop at different rates!