Body composition calculator
Body Fat Calculator
Frequently asked questions
- How does the Navy body-fat method work?
- It uses sex-specific log equations from circumference measurements (neck, waist, and hips for women) plus height. Results are estimates and can differ from DEXA or other lab methods.
- How accurate is a circumference body-fat estimate?
- Tape method accuracy depends on consistent landmarking and measurement technique. Treat the number as a trend tool, not a precise medical diagnosis.
- Who should not rely on this estimate alone?
- Anyone needing clinical body-composition assessment should use clinician-directed methods. This page is general fitness guidance for adults.
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.
Body fat calculator form
Body fat calculator results
Estimated body fat16.1%
Fitness range for adult men. Approx. fat mass 12.9 kg, lean mass 67.1 kg.
Body fat category reference
| Category | Body fat |
|---|---|
| Essential fat | < 6% |
| Athletes | 6–13% |
| Fitness | 14–17% |
| Average | 18–24% |
| Above average | 25%+ |