This Calculator is designed to give the approximate percentage of body fat, based on weight and waist size as compared to tables published by the American Medical Association. It does not use any sort of caliper or hydro displacement (known as hydrostatic weighing); therefore, some people say it is not as accurate. According to the AMA, it is a pretty accurate guideline but is no substitute for seeing a doctor. To do this self evaluation, select your gender on the calculator. Enter your present weight and waist size. Click on Calculate for the approximate body fat percentage to be displayed; compare the result to the table below. You may change the values or click on Clear Values to try again.