Why use this percent body fat calculator over other means of determining your body fat? This method is not as accurate as the skinfold method with the Accu Measure Body Fat Calipers It is not as convenient as body fat scales, but it has the advantage of less operator error for some people. No method is extremely accurate for measuring your percent body fat so why not use them all and compare.
Here is the best calculator I have found at: https://www.calculator.net/body-fat-calculator.html
Just remember this is a measurement that is very difficult no matter which method you use.