Body Fat Calculator..does this sound right?

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.
The U.S. Marine Corps and U.S. Army also rely on the height and circumference method. For males, they measure the neck and waist just above the navel. Females are measured around the hips, waist, and neck. These measurements are then looked up in published tables, with the individual's height as an additional parameter. This method is used because it is a cheap and convenient way to implement a body fat test throughout an entire service.
Methods using circumference have little acceptance outside the Department of Defense due to their negative reputation in comparison to other methods. The method's accuracy becomes an issue when comparing people with different body compositions, those with larger necks artificially generate lower body fat percentage calculations than those with smaller necks.