Body Fat Calculator

This calculator estimates body fat percentage for adults who have a tape measure but no access to laboratory body-composition testing.

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Measure height, neck, and waist, plus hips for women, using the same unit throughout. Keep the tape level and snug without compressing the skin, and repeat each measurement for a more dependable average.

Using the U.S. Navy method with measurements in inches, male body fat percentage = 86.010 x log10(waist - neck) - 70.041 x log10(height) + 36.76. Female body fat percentage = 163.205 x log10(waist + hip - neck) - 97.684 x log10(height) - 78.387.

Worked example

A man with a 36-inch waist, 15-inch neck, and 70-inch height has an estimated body fat percentage of about 20.3 percent. Small measurement changes can shift the result, so consistent tape placement matters.

Common questions

Is tape-measure body fat accurate?

It is useful for estimating trends, but it can differ from a clinical measurement by several percentage points. Use the same method and conditions each time rather than treating one result as exact.

Where should I measure my waist?

Follow the calculator's stated measurement site, since formulas are tied to specific locations. Measure after a normal exhale, without pulling in your stomach or tightening the tape.

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