Estimate your body fat percentage using the U.S. Navy method — all you need is a tape measure.
U.S. Navy method
The U.S. Navy method provides an estimate only. Accuracy varies with body type. For precise body fat measurement, consult a professional using DEXA or hydrostatic testing.
Body fat percentage represents the proportion of your total body weight that is fat tissue. Unlike BMI, which only considers overall weight, body fat percentage gives a more meaningful picture of body composition by distinguishing between fat mass and lean mass (muscle, bone, water, organs).
Maintaining a healthy body fat percentage is important for hormonal function, organ protection, temperature regulation, and energy storage. Too little body fat can be as dangerous as too much — essential fat is needed for basic physiological function.
Developed by the United States Navy for fitness assessments, this method uses circumference measurements to estimate body fat. It requires waist, neck, and height measurements for men, with an additional hip measurement for women.
For men: %BF = 495 / (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
For women: %BF = 495 / (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450
| Category | Men | Women |
|---|---|---|
| Essential fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Above average | 25%+ | 32%+ |
The U.S. Navy method has a typical error margin of 3–4% compared to gold-standard methods like DEXA (dual-energy X-ray absorptiometry) or hydrostatic weighing. It tends to be less accurate at the extremes — very lean or very high body fat individuals may get less reliable estimates.
Factors like hydration, recent meals, and even the time of day can affect measurements. For the most consistent results, measure at the same time of day under similar conditions. For precise body fat assessment, consider DEXA scanning or bod pod testing through a healthcare provider.
For men, 14–24% is generally healthy. For women, 21–32%. Essential fat minimums are about 2–5% for men and 10–13% for women.
It has a typical margin of error of 3–4% compared to DEXA scanning. More accurate within normal ranges, less accurate at extremes.
Men and women store fat differently. Women need a hip measurement because they naturally carry more fat on hips and thighs. The formula constants are calibrated for each sex's fat distribution patterns.