Estimate your body fat percentage from a few circumference measurements, using the U.S. Navy method.
This method estimates body fat from just a few circumference measurements — neck, waist, and (for women) hip — rather than requiring specialized equipment. It was developed at the Naval Health Research Center and remains a common estimation method precisely because it only needs a tape measure. It's an estimate, not a precise measurement — tools like bioelectrical impedance or hydrostatic testing are more accurate but far less accessible.
Small measuring errors get amplified by the formula's math, so consistency matters: measure to the nearest 1/4 inch (0.5 cm), keep the tape snug but not compressing the skin, and don't pull your stomach in when measuring your waist.
The U.S. Navy (circumference) method and the BMI-based method are two independent estimation approaches. They usually land close together, but BMI doesn't distinguish fat from muscle, so the two can diverge more for very muscular or very lean people.
Essential fat is roughly 2-5% for men and 10-13% for women — the minimum needed for basic health. Healthy ranges above that vary by age, activity level, and goals; see the reference table for the American Council on Exercise's categories.
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