Body Fat Calculator

Understanding Body Fat Percentage

Body fat percentage tells you how much of your total body weight comes from fat tissue versus lean mass, which includes muscle, bone, water, and organs. Unlike BMI, which only considers height and weight, body fat percentage provides a much more meaningful picture of your health and fitness level. Two people can weigh the same but have very different body compositions, and body fat percentage captures that distinction.

This calculator uses the US Navy method, a widely validated formula developed by the United States Navy for assessing military fitness. The method requires simple circumference measurements that you can take with a flexible tape measure. For men, the formula uses waist and neck measurements relative to height. For women, it adds hip circumference because women naturally store more fat in the hip region. All measurements should be taken on bare skin, standing relaxed, at consistent times to ensure reliable results.

Body fat categories differ between men and women due to biological differences. Men carry essential fat at 2 to 5 percent, while women need 10 to 13 percent for normal hormonal and reproductive function. Athletic ranges, fitness ranges, and average ranges are all higher for women. Dropping below essential fat levels is dangerous and can impair immune function, hormonal balance, and organ health. For most people pursuing general fitness, aiming for the fitness range is both healthy and achievable through a combination of regular strength training and balanced nutrition. Track your body fat over time rather than focusing on a single reading, as measurement variability is normal.