Calculate body fat percentage using the US Navy method
A body fat calculator estimates what percentage of your body weight is fat, using the US Navy method — a formula based on simple tape-measure measurements rather than special equipment. Where weight or BMI only tell you a single number, body fat percentage tries to separate fat from everything else (muscle, bone, water), which is a more meaningful picture of body composition. You enter your measurements and the calculator applies the established formula to produce an estimate and the category it falls into.
The US Navy method works from circumference measurements — typically neck and waist, plus hips for women — along with height, because the proportions between these correlate with body fat in the population the formula was built on. It is popular precisely because it needs only a tape measure and gives a reasonable estimate without a scan or calipers. That said, it is an estimate from a population formula, not a precise measurement of your individual body, and results vary with how accurately you measure. This tool calculates everything in your browser, so your details stay private.
It uses circumference measurements — neck and waist for men, plus hips for women — together with height, in a formula derived from population data. The ratios between these measurements correlate with body fat, so the method estimates the percentage without special equipment.
BMI only uses height and weight, so it cannot tell fat from muscle — a muscular person can read as overweight. Body fat percentage tries to estimate composition directly, giving a more meaningful picture of how much of your weight is fat versus lean mass.
It is a reasonable estimate from a population formula, not a precise measurement like a DEXA scan. Accuracy depends heavily on measuring carefully and consistently, and the formula fits some bodies better than others, so treat the result as an approximate guide and a way to track change.
No. It is an informational estimate, not personalised medical or fitness advice. Healthy body fat ranges vary with age, sex and individual factors, so for health or training decisions consult a doctor or qualified professional rather than relying on a single number.
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