CalcLibrary

Body Fat Calculator

Calculate your body fat percentage using the US Navy method. Enter your measurements to estimate body fat and see how you compare to fitness categories.

Units
in
in
in
Examples

175 cm, neck 38 cm, waist 78 cm — about 11.0% (athletic).

Body Fat Percentage
11 %
Category
Athletic

11.0% body fat falls in the "athletic" range for your gender.

Estimate only — not a medical assessment. This tape-measure estimate ignores age, ethnicity, and individual fat distribution. For clinical decisions, use DEXA, hydrostatic weighing, or talk to a healthcare provider before changing your diet or training based on this result.

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Examples

How It Works

Formula

BFmale=86.010×log⁡10(w−n)−70.041×log⁡10(h)+36.76\text{BF}_{\text{male}} = 86.010 \times \log_{10}(w - n) - 70.041 \times \log_{10}(h) + 36.76

BFfemale=163.205×log⁡10(w+H−n)−97.684×log⁡10(h)−78.387\text{BF}_{\text{female}} = 163.205 \times \log_{10}(w + H - n) - 97.684 \times \log_{10}(h) - 78.387

Variables

BF\text{BF}

Body fat percentage(%)

ww

Waist circumference(in)

nn

Neck circumference(in)

HH

Hip circumference (women only)(in)

hh

Height(in)

The US Navy method uses logarithmic formulas applied to circumference measurements and height, all in inches. Metric entries are converted to inches before the formula is applied. For men, it uses neck and waist; for women, it adds hip circumference. The result is compared against standard body fat categories to classify your fitness level.

The US Navy coefficients are calibrated to inches, so any centimetre input is converted via 1 in=2.54 cm1\,\text{in} = 2.54\,\text{cm} before the equation is evaluated. The male formula uses waist minus neck; the female formula adds hip circumference to capture sex-specific fat distribution. The resulting percentage is then matched to a fitness band (essential, athletic, fitness, average, above average).

Frequently Asked Questions

01What is the US Navy method?
The US Navy method estimates body fat percentage from simple circumference measurements (neck, waist, and hip for women) combined with height. It is useful for screening and trend tracking.
02How accurate is this method?
This is a tape-measure estimate, not a clinical body-composition test. It is less direct than DEXA scans or hydrostatic weighing but more accessible for tracking trends over time.
03Why do women need hip measurements?
Women typically carry more fat in the hip and thigh area. The hip circumference helps account for this difference in fat distribution, making the estimate more accurate for women.
04What body fat percentage is healthy?
Treat the category label here as a rough fitness-oriented band, not a medical judgment about healthy or unhealthy body fat.
05How should I measure my circumferences?
Use a flexible tape measure. Measure your neck at the narrowest point below the Adam's apple. Measure your waist at the navel level. Measure hips at the widest point. Keep the tape snug but not tight, and measure on bare skin.

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