Body Fat Percentage Calculator

The U.S. Navy method (developed by Hodgdon & Beckett in 1984) estimates body fat percentage using simple circumference measurements instead of expensive scans. For men it uses neck and abdomen circumferences plus height; for women it uses neck, waist, hip, and height. The measurements feed into a logarithmic regression equation that was validated against hydrostatic (underwater) weighing. It is one of the most accurate tape-measure methods available, typically within ±3% of lab results.

The U.S. Navy equation is accurate to roughly ±3% for most adults when measurements are taken correctly. Its accuracy is comparable to skinfold caliper methods and better than simple BMI. Accuracy depends heavily on measurement technique: the tape should sit snugly but not compress the skin, and each site must be measured at the exact location described. For the highest accuracy, have someone else take the measurements and repeat each one 2–3 times, averaging the results.

According to the American Council on Exercise (ACE), for men: essential fat is 2–5%, athletes 6–13%, fitness 14–17%, average 18–24%, and obese 25%+. For women, the ranges are higher because of essential reproductive fat: essential 10–13%, athletes 14–20%, fitness 21–24%, average 25–31%, and obese 32%+. The "fitness" range is generally considered the healthiest target for most adults.

Neck: measure just below the larynx (Adam's apple), with the tape sloping slightly downward toward the front. Men's abdomen/waist: measure at the level of the navel (belly button). Women's waist: measure at the narrowest point of the torso. Hip (women only): measure at the widest point of the hips and buttocks. In all cases, stand straight, breathe normally, and keep the tape horizontal and snug — not tight enough to indent the skin.

You need a flexible tape measure and this calculator. Take each measurement 2–3 times and use the average. Enter your height and the circumference measurements (neck and abdomen for men; neck, waist, and hip for women). Our free calculator applies the Navy formula instantly. For more precise results, measure in the morning, before exercise, and avoid measuring right after a workout when muscle pumps and fluid shifts can skew the numbers.

For many people, yes. BMI only considers height and weight and cannot distinguish muscle from fat, so muscular athletes are often misclassified as overweight. Body fat percentage directly measures fat relative to total mass, which is the more meaningful health metric. However, the Navy method is an estimate — for the most precise measurement, methods like DEXA scans, hydrostatic weighing, or BIA scales are used, though they cost more or require equipment.

Body Mass Index (BMI) is a simple ratio of weight to height (kg/m²) that classifies weight categories but does not measure fat directly. Body fat percentage is the actual proportion of your total weight that is fat. Two people with the same BMI can have very different body fat percentages — for example, a bodybuilder and a sedentary person of the same height and weight. Tracking body fat % gives you a clearer picture of body composition changes than the scale alone.

Yes. The calculator is 100% free with no registration, and every calculation runs entirely in your browser — no data is ever sent to a server. If you choose to save results, they are stored only in your browser's localStorage, and you can export, import, or clear your history at any time.