BMI indicates your health risks by comparing your height and weight. Males with a BMI above 27.8 and women over 27.3 are considered overweight. Males with a BMI less than 20.7 and women below 19.1 are classified as underweight.

There are limitations to BMI so it's important to realize that it is only an estimation of body fat. People who have valid reasons for maintaining weight outside of normal ranges (pregnant or breast feeding women, competitive athletes, body builders and people who are chronically ill) may experience inaccurate BMI values. People with a high percentage of muscle mass may appear overweight using BMI because muscle weighs more than fat.