A person's body mass index (BMI) is a rough indication of body fat calculated using height and weight. It can help quickly determine a person's risk for becoming overweight or obese, which are serious health conditions affecting over 100 million adult Americans.
Once information is gathered on a person's BMI, it can be interpreted for adults using standard weight status categories that are the same for all ages and for both men and women. A normal BMI ranges from 18.5 to 24.9. Anything from 25.5 to 29.9 is overweight, and a reading of 30.0 and higher is considered obese.
(For more information on this topic, click BMI. This article describes in more detail how this number is calculated, the different ways it is interpreted, and the health complications that overweight and obesity can cause.)