Body Fat Calculator

Measure your neck, waist and (for women) hip with a tape measure to estimate your body fat percentage. Estimate only, not medical advice.

Source: NCBI Bookshelf – Body Composition in the Military Services ↗

This result is an estimate only. Check with your bank or the relevant authority before making decisions.

How it is calculated

This calculator uses the US Navy method with all measurements in centimetres:

Male: 495 ÷ (1.0324 − 0.19077 × log10(waist − neck) + 0.15456 × log10(height)) − 450
Female: 495 ÷ (1.29579 − 0.35004 × log10(waist + hip − neck) + 0.22100 × log10(height)) − 450

If the measurements give zero or a negative value inside log10, the calculator shows an error. It is a tape-measure estimate, and DEXA scans are more accurate. Estimate only, not medical advice.

Worked example

Male, height 178 cm, neck 38 cm, waist 85 cm: body fat 16.4% (16.44)
Female, height 165 cm, neck 33 cm, waist 72 cm, hip 98 cm: body fat 26.9% (26.92)

Why your number may differ

This is an estimate from a tape measure, so how and where you measure changes the result. DEXA scans are more accurate. Estimate only, not medical advice.

Frequently asked questions

How should I measure?

Use a tape measure and record centimetres. Inconsistent measuring will affect the result.

Is the result accurate?

It is only a tape-measure estimate. DEXA scans are more accurate. Estimate only, not medical advice.

Why do women need to enter a hip measurement?

The US Navy formula for women uses waist, hip and neck, while the male formula uses only waist and neck.