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Body Fat % Calculator

Estimate body fat percentage using the US Navy method

Body Composition
Body Fat % Calculator
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What This Calculator Measures

This calculator estimates your body fat percentage using the US Navy circumference method. Body fat percentage is a more meaningful measure of body composition than BMI because it distinguishes between fat mass and lean mass.

Diagram showing how the Body Fat % Calculator works
How the Body Fat % Calculator works

How It Works

The US Navy method uses the following formula for males:

**BF% = 495 / (1.0324 - 0.19077 x log10(waist - neck) + 0.15456 x log10(height)) - 450**

All measurements are in centimeters. The formula was developed from data on US Navy personnel and validated against hydrostatic weighing.

For example: waist 80 cm, neck 38 cm, height 180 cm yields approximately **15%** body fat.

Body Fat % (Male)Category
2-5%Essential fat (competition stage)
6-13%Athletic
14-17%Fitness
18-24%Average
25%+Above average

Limitations

•This formula is for males only. The female formula requires an additional hip circumference measurement.
•Accuracy is roughly ±3-4% compared to DEXA scans. It is a screening tool, not a precision measurement.
•Where you carry fat matters. If you store disproportionate fat around the waist, this method may overestimate your body fat relative to someone with the same percentage distributed more evenly.
•Measurements should be taken at consistent times (morning, relaxed) for best accuracy.