There also exist formulas for estimating body fat percentage from an individual's weight and girth measurements. For example, the U.S. Navy circumference method compares abdomen or waist and hips measurements to neck measurement and height and other sites claim to estimate one's body fat percentage by a conversion from the body mass index. In the U.S. Navy the method is known as the "rope and choke." There is limited information, however, on the validity of the "rope and choke" method because of its universal acceptance as inaccurate and easily falsified.