Estimate your body fat percentage using the U.S. Navy circumference method, a widely trusted technique that requires only a tape measure. Enter your height, weight, neck, and waist measurements, and women also add hip circumference, to receive your body fat percentage and a category rating from essential fat through athletic, fit, average, to obese. The app also calculates your lean mass and fat mass in absolute weight so you can track meaningful body composition changes over time. Both metric and imperial units are supported for all inputs.