The US Navy method uses body circumference measurements to estimate body fat percentage. It was developed by Hodgdon and Beckett at the Naval Health Research Center.
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–5% | 10–13% |
| Athletic | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
A 6'0" (183 cm) male measures: neck = 16" (40.6 cm), waist = 34" (86.4 cm). Plugging into the formula: BF% = 86.010 × log₁₀(34 − 16) − 70.041 × log₁₀(72) + 36.76 = 86.010 × log₁₀(18) − 70.041 × log₁₀(72) + 36.76 ≈ 86.010 × 1.2553 − 70.041 × 1.8573 + 36.76 ≈ 107.95 − 130.07 + 36.76 ≈ 14.6% — solidly in the Fitness category.
The US Navy method is accurate to within ±3–4 percentage points for most people. Compare that to DEXA scan (X-ray bone density scan, ±1–2%, gold standard but expensive), hydrostatic weighing (underwater weighing, ±1.5–3%, lab setting required), skinfold calipers (±3–4%, requires trained technician), and simple BMI (no fat measurement at all). The Navy method's main advantage is that it requires only a tape measure and is repeatable at home — making it ideal for tracking trends over time.
Subcutaneous fat sits just under your skin — it's the fat you can pinch. While excess subcutaneous fat affects appearance and can increase health risk at very high levels, it is far less dangerous than visceral fat, which wraps around your internal organs. Visceral fat is strongly linked to insulin resistance, Type 2 diabetes, heart disease, and inflammation. A high waist circumference (above 40" for men, 35" for women) is the primary warning sign of excess visceral fat. The Navy method estimates total body fat, not visceral fat specifically — a DEXA scan or MRI can distinguish between the two.
Disclaimer: This calculator provides estimates for informational purposes only. Results are not a substitute for professional medical assessment. Consult a qualified healthcare provider for medical advice regarding body composition and health.
This free body fat percentage calculator uses the US Navy circumference method to estimate your body fat percentage accurately without any equipment. Simply enter your height, neck, waist, and hip measurements to instantly calculate your fat percentage and see which fitness category you fall into — essential, athletic, fit, acceptable, or obese.
The body fat calculator is widely used by fitness enthusiasts, athletes, and health-conscious individuals tracking their body composition over time. Unlike BMI, which only uses height and weight, the fat percentage calculator accounts for body shape and distribution, giving a more meaningful picture of your overall fitness and health.
Healthy ranges differ by sex. For men: 6–13% is athletic, 14–17% is fitness level, 18–24% is acceptable, and 25%+ is obese. For women: 14–20% athletic, 21–24% fitness, 25–31% acceptable, 32%+ obese. Essential fat (the minimum for survival) is 2–5% for men and 10–13% for women.
The US Navy method is accurate to within ±3–4 percentage points compared to DEXA scan (gold standard at ±1–2%). It is significantly more accurate than BMI for assessing body composition because it accounts for body shape, not just height and weight. Consistency matters most — take measurements under the same conditions each time to reliably track changes.
Neck: just below the larynx (Adam's apple), angled slightly downward at the front. Waist (men): at the navel. Waist (women): at the narrowest point, usually above the navel. Hips (women only): at the widest point of the buttocks. Take each measurement twice and average them. Use a flexible tape measure held snug but not compressing the skin.
Subcutaneous fat sits under the skin and is the type you can pinch. Visceral fat surrounds your internal organs inside the abdominal cavity. Visceral fat is far more dangerous — it is directly linked to insulin resistance, Type 2 diabetes, heart disease, and chronic inflammation. A waist circumference above 40" (men) or 35" (women) is a key warning sign of excess visceral fat.
Yes, for most purposes. Body fat percentage directly measures the proportion of fat in your body, distinguishing it from lean mass (muscle, bone, organs). BMI only uses height and weight, so a muscular athlete can be flagged as "overweight" or "obese" by BMI despite having low body fat. Use both metrics together for a fuller picture.
Yes — this is called body recomposition, and it works best for beginners, those returning after a break, or people with higher body fat percentages. Eat near maintenance calories, train with progressive resistance, and consume 0.7–1g of protein per pound of bodyweight. Advanced athletes find simultaneous muscle gain and fat loss harder and typically alternate between dedicated bulk and cut phases.
Most men can see defined abs at 10–12% body fat. At 14–15% there may be a faint outline with good lighting. For women, visible abs typically appear around 16–19% due to naturally higher essential fat levels. Genetics, abdominal muscle development, and water retention all affect how defined abs look at any given body fat percentage.
Once every 2–4 weeks is ideal for tracking progress without obsessing over short-term fluctuations. Body fat doesn't change significantly day-to-day, and daily measurements are influenced heavily by water retention and meal timing. Always measure at the same time of day (morning, before eating or drinking) under the same conditions for the most consistent results.