Body Fat Calculator
Estimate adult body fat percentage with the U.S. Navy circumference method (Hodgdon–Beckett). Measure height, neck, and waist — plus hips for women — then optionally add bodyweight to see fat mass and lean mass.
How the formula works
This page uses the metric (centimeter) Navy equations. For men: 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450. For women: 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.221 × log10(height)) − 450. Imperial inputs are converted to centimeters before the math runs.
Measure neck just below the larynx, waist at the navel for men or the narrowest point for women, and hips at the widest point (women). Keep the tape snug but not compressing. This is a population estimate with typical error of a few percentage points versus lab methods — not a diagnosis and not a substitute for clinical assessment.
Fitness range for adult men. Approx. fat mass 12.9 kg, lean mass 67.1 kg.
| Category | Body fat |
|---|---|
| Essential fat | < 6% |
| Athletes | 6–13% |
| Fitness | 14–17% |
| Average | 18–24% |
| Above average | 25%+ |
Use the estimate with training tools
Body fat percentage is one context signal. Pair it with strength programming, protein targets, and calorie planning rather than chasing a single number.