What is a BMI?A BMI (body mass index) is a calculation based on your weight and height. While it's hard to directly measure fat on the body, a BMI can provide a good estimate.To measure BMI, your health care provider may use an online tool or an equation that uses your weight and height information. You can measure your own BMI in much the same way by using an online BMI calculator.Your results will fall into one of these categories:Below 18.5: Underweight18.5-24.9: Healthy weight25 -29.9: Overweight30 and above: Obese40 or higher: Severely obese, also known as morbidly obeseBMI is also used to diagnose obesity in children, but it is figured out differently than in adults. Your child's health care provider will calculate BMI based on your child's age, sex, weight, and height. He or she will compare those numbers with the results of other children with similar characteristics.The results will be in the form of a percentile. A percentile is a type of comparison between an individual and a group. For example, if your child has a BMI in the 50th percentile, it means 50 percent of children of the same age and sex have a lower BMI. Your child's BMI will show one of the following results:Less than the 5th percentile: Underweight5th-84th percentile: Normal Weight85th-94th percentile: Overweight95th percentile and higher: Obese
