About Body Fat Calculator
Estimates body fat percentage using three different methods: the U.S. Navy formula (circumference-based logarithmic calculation, generally considered most accurate of the three), the U.S. Army formula, and a BMI-derived estimate. Supports metric and imperial units with gender-specific calculations—women need a hip measurement that men don’t. Results are categorized as Essential Fat, Athletes, Fitness, Average, or Obese with gender-adjusted ranges.
- Navy method uses logarithmic formula: 495 ÷ (1.0324 – 0.19077×log₁₀(waist–neck) + 0.15456×log₁₀(height)) – 450 for men; women’s formula adds hip circumference
- Army method: 86.010×log₁₀(waist–neck) – 70.041×log₁₀(height) + 36.76 for men, with a different formula incorporating hip for women
- BMI-based estimate: 1.20×BMI + 0.23×age – 10.8×gender factor – 5.4 (least accurate, useful when you don’t have a tape measure)
- Gender-specific body fat categories: Essential Fat (<6% male / <14% female), Athletes (6–13% / 14–20%), Fitness (14–17% / 21–24%), Average (18–24% / 25–31%), Obese (>25% / >32%)
- Metric and imperial unit support with automatic conversion
Frequently Asked Questions
- Which method should I trust?
- The Navy method is the most validated of the three for general use. The Army method is similar but tuned for military fitness standards. The BMI-based estimate is the least accurate—it’s a rough proxy when you can’t take circumference measurements. None of these replace a DEXA scan or hydrostatic weighing for precision.
- Why do women need a hip measurement?
- Women store more essential fat around the hips and thighs. The Navy and Army formulas account for this by including hip circumference in the female calculation. Without it, the formula would systematically overestimate body fat in women.