The most common way to find out whether you're overweight or obese is to figure out your body mass index (BMI). BMI is an estimate of body fat, and it's a good gauge of your risk for diseases. The higher your BMI, the higher your risk of disease.
To check your child's BMI, click here.
Source Source "The Practical Guide Identification, Evaluation, and Treatment of Overweight and Obesity in Adult," October 2000. National Institutes of Health National Heart, Lung, and Blood Institute North American Association for the Study of Obesity