The US Navy method estimates body fat from tape measurements. With measurements in inches, men use 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76, and women use 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387. This calculator converts centimeters to inches for you. It is an estimate and can be off by a few percentage points compared with DEXA scans or calipers.
Commonly used ranges for men are about 6-24% and for women about 14-31%, depending on age and fitness. Categories here follow the American Council on Exercise: essential fat, athletes, fitness, average and obese.
Stand relaxed, keep the tape snug but not tight, and measure to the nearest half centimeter. Take each measurement twice and average.
See also: BMI Calculator · BMR and Calorie Calculator · Age Calculator