Find your body fat percentage with the trusted US Navy method — plus fat mass, lean mass and your fitness category.
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US Navy Method
Completely Free
Your Body Fat (US Navy)
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—
Fat Mass
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kg
Lean Mass
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kg
BMI
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kg/m²
BMI Method BF
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% (needs age)
Body Fat Categories (ACE)
Category
Men
Women
Essential fat
2–5%
10–13%
Athletes
6–13%
14–20%
Fitness
14–17%
21–24%
Average
18–24%
25–31%
Obese
25%+
32%+
The US Navy method is an estimate based on body measurements. For medical accuracy use DEXA or hydrostatic weighing. Not a substitute for professional advice.
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Frequently Asked Questions
The US Navy method estimates body fat percentage from a few tape measurements — your height, neck and waist (plus hips for women). It uses a logarithmic formula validated against more expensive methods. For men: %BF = 495 / (1.0324 − 0.19077·log10(waist−neck) + 0.15456·log10(height)) − 450.
Measure your neck just below the larynx, your waist at the navel (men) or the narrowest point (women), and hips at the widest point (women only). Keep the tape snug but not compressing the skin, and stand relaxed without holding your breath.
According to ACE, for men: 2–5% is essential, 6–13% athletes, 14–17% fitness, 18–24% average, and 25%+ is obese. For women: 10–13% essential, 14–20% athletes, 21–24% fitness, 25–31% average, and 32%+ is obese. Women naturally carry more essential fat than men.
Fat mass is the total weight of fat in your body (body weight × body fat %). Lean (fat-free) mass is everything else — muscle, bone, organs and water. This calculator shows both so you can track changes from training or diet.
The US Navy method is a good estimate and is far more useful than BMI alone because it accounts for body shape. It is typically within 3–4% of a DEXA scan for most people. For medical accuracy, use DEXA or hydrostatic weighing. Treat the result as a guideline.
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