How to Calculate Body Fat & Percentage of Weight Lost

There are two ways to determine the amount of body fat you have: the body mass index (BMI) and percentage of body fat. BMI is the standard used by the World Health Organization to classify adults as underweight, overweight and obese. The U.S. Navy and U.S. Army developed a percentage of body fat formula. Calculating the percentage of weight you have lost, however, is simple and requires no complex formula.