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Health · Body Fat

Body Fat Calculator

Estimate body fat percentage from body measurements.

Body Fat Calculator

Choose your sex and unit system, enter your height, neck, and waist (and hip, for women), then select Calculate.

How this is calculated

This uses the U.S. Navy circumference method: Men: BF% = 495 ⁄ (1.0324 − 0.19077×log₁₀(waist−neck) + 0.15456×log₁₀(height)) − 450 Women: BF% = 495 ⁄ (1.29579 − 0.35004×log₁₀(waist+hip−neck) + 0.221×log₁₀(height)) − 450 Results are also classified using the American Council on Exercise's standard body-fat categories (Essential fat, Athletes, Fitness, Average, Obese), which differ between men and women.

Examples

A man with a 95 cm waist, 50 cm neck, and 179 cm height has an estimated body fat of about 15% — in the "Fitness" range for most adult men.

About this calculation

The U.S. Navy method (Hodgdon & Beckett, 1984) estimates body fat from circumference measurements alone, without specialized equipment. It's a widely used estimate, not a clinical measurement — actual body composition can vary from this estimate.

Related tools

More calculators are on the way — browse everything planned on the Home page.

Frequently asked questions

Where exactly should I measure?

Neck: just below the larynx (Adam's apple). Waist: at the narrowest point, or at the navel if there's no clear narrowing. Hip (women only): at the widest point around the hips and buttocks.

Why does the calculator say my input is invalid?

Every measurement must be a positive number, and the waist measurement (plus hip, for women) must be larger than the neck measurement — otherwise the formula has no valid result.

What do the body-fat categories mean?

They're the American Council on Exercise's standard ranges: Essential fat is the minimum needed for basic health; Athletes and Fitness describe increasingly lean, trained physiques; Average covers most healthy adults; Obese flags a level linked to higher health risk. Ranges differ between men and women because essential fat needs differ by sex.