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Body Composition

Body Fat Calculator — Navy Method

Calculate your body fat percentage using the US Navy circumference method — the most accessible scientifically validated formula that requires only a tape measure. Supports metric and imperial.

US Navy Body Fat Calculator

Circumference method — no calipers needed

Units
Sex
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Body Fat Percentage

The US Navy formula uses simple circumference measurements that anyone can take at home. It was developed as a field-practical method for the US military and is regularly used by sports coaches, personal trainers, and fitness enthusiasts worldwide. It requires only a tape measure.

Body Fat % Categories

CategoryMenWomen
Essential Fat2–5%10–13%
Athletic6–13%14–20%
Fitness14–17%21–24%
Acceptable18–24%25–31%
Obese25%+32%+

How the US Navy Body Fat Formula Works

The US Navy method uses logarithmic equations based on circumference measurements at specific body sites. For men, the formula uses waist and neck measurements against height. For women, hip measurement is added because women carry more fat in the hips/thighs region. The formula assumes that circumference at these sites accurately reflects total body fat distribution — an assumption that holds well for most people in the 10–40% body fat range but is less accurate at extremes.

Frequently Asked Questions

Men: measure waist at the level of the navel. Women: measure waist at the narrowest point (natural waist, typically 2.5 cm above the navel). Both: exhale gently, stand relaxed (do not suck in), keep tape horizontal. Do not compress the skin. Consistency in measurement location is crucial for accurate tracking.
Both methods have similar accuracy (±3–4% vs DEXA). Skinfold calipers require skill and specific landmark knowledge; measurement error between technicians is significant. The Navy method is more reproducible with less training, but both are inferior to DEXA, BodPod, or hydrostatic weighing for absolute accuracy. For relative tracking over time, the Navy method is excellent when measurements are taken consistently.
The US Navy method has an accuracy of ±3–4% compared to DEXA or hydrostatic weighing in most studies. It tends to underestimate body fat in lean individuals and overestimate in obese individuals. For most people in the 15–35% body fat range, it provides a reliable estimate without expensive equipment. Measurement consistency (measuring at the same time, same conditions) is critical for tracking progress over time.
Yes — this calculator accepts both centimetres (metric) and inches (imperial). Select your preferred unit system at the top of the calculator and enter your measurements accordingly. The underlying Navy formula always works in centimetres internally; the calculator converts your inches to centimetres automatically before computing the result.

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