Body Fat Calculator

Estimates body fat percentage from neck, waist, and hip measurements using the US Navy circumference method.

Body fat percentage estimates what share of your weight is fat vs. lean tissue. Categories are general population ranges — athletes and very lean individuals may fall outside "average" without being unhealthy.

1. Choose units and sex, then enter height and weight.
2. Measure neck, waist, and hip (women) at the specified points.
3. View body fat %, fat mass, lean mass, and category.

U.S. Navy circumference equations

Men, in inches: 86.010 × log₁₀(waist − neck) − 70.041 × log₁₀(height) + 36.76. Women, in inches: 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387.

Source. Hodgdon and Beckett, Naval Health Research Center, 1984. Measurements are inches and the logarithm is base 10. Men: 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. The linked paper prints the men's equation as used here. Its women's line leaves out the hip measurement; the women's equation on this page includes it. The category bands on this page are the American Council on Exercise ranges. Hodgdon and Beckett, as quoted in a Marine Corps methods paper.

Updated November 1, 2026

A male at 5'10" with 15" neck and 34" waist estimates to roughly 18% body fat (average range).

• Measure consistently — tape snug but not compressing skin.
• Not a substitute for DEXA scans or medical assessment.

What is a healthy body fat percentage?

It varies by sex and age. For general fitness, many adults aim for the fitness or average ranges in the table above — but individual goals should involve a healthcare provider.

How accurate is the Navy body fat method?

It is a practical field estimate — typically within a few percentage points of more precise methods for most people, but less accurate at very low or very high body fat.