Body Fat Estimate (3 Skinfolds) Calculator View Calculator Calculating your body fat percentage by taking some measurements from the fat-storing zones will reveal your fitness level more accurately than scale weight alone. Combine these measurements with your gender, weight, and age and this calculator will find your percent of body fat, how much of your weight is lean mass and how much is fat mass, and your general fitness category.While the water displacement test is the most accurate way to determine body fat percent, skinfold tests are valuable because they can be done at home with the same person measuring each time, providing good measurements to monitor body composition changes over time. Learn more about putting this calculator or other calculators on your website.