Body Fat Percentage Calculator

How it works

Body fat percentage is the proportion of your total body weight that is fat — including essential fat (organs, nerves, marrow) and storage fat (subcutaneous and visceral). It is a far better indicator of body composition than weight or BMI alone, because two people of identical weight can have very different fat-to-muscle ratios.

This calculator uses the US Navy circumference method, originally developed for military fitness assessments. It uses three (men) or four (women) tape-measure inputs to estimate body fat to within roughly ±3 percentage points of more expensive methods like DEXA scans. The formula uses neck and waist (and hip, for women) measurements together with height, taking advantage of the fact that fat distributes predictably around these landmarks.

For accurate measurements, use a flexible non-stretchable tape: measure your neck just below the larynx with the tape angled slightly downward, your waist at the navel for men or at the narrowest point for women, and your hips at the widest point of the buttocks. Stand naturally — don't suck in. Take each measurement three times and average them.

Healthy ranges: men 10–20%, women 18–28% (essential fat is much higher in women due to reproductive needs). Athletes often live below these ranges (men 6–13%, women 14–20%) but this is not generally healthier than the standard range. Below ~5% in men or 12% in women body fat becomes physiologically dangerous.

For higher accuracy, DEXA scans are the practical gold standard (~$50–150). Bioelectrical impedance scales are convenient but very dependent on hydration. Skinfold calipers are inexpensive and reasonably accurate when used by a trained tester. The US Navy method's main advantage is requiring nothing more than a tape measure.