Body fat calculator
Enter your height and your neck and waist circumferences (plus hip for women) and get a US Navy method estimate of your body-fat percentage with its reference category. It is an orientative estimate: precise measurement requires clinical methods such as DEXA.
Enter your measurements to see the estimate.
US Navy circumference method. Orientative estimate with a ±3–4 % typical error; precise measurement uses clinical methods (DEXA, plethysmography). ACE reference categories.
The US Navy method estimates body fat from body circumferences and height. No special scale or calipers needed — just a measuring tape. Its typical error is around ±3–4 % versus clinical methods, enough as a reference to track progress.
Measure the neck just below the Adam's apple, the waist at navel height and, for women, the hip at its widest point. Always measure under the same conditions so week-to-week comparison makes sense.
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Frequently asked questions
How does the US Navy body-fat method work?+
It uses height plus neck and waist circumferences (and hip for women) in a logarithmic formula developed by the US Navy. It doesn't measure fat directly — it estimates it from the relationship between those measurements.
What body-fat percentage is healthy?+
As a general reference (ACE): for men, 6–13 % is athletic, 14–17 % fitness and 18–24 % average; for women, 14–20 % athletic, 21–24 % fitness and 25–31 % average. These are orientative bands — the optimum depends on each person and context.
How accurate is this method?+
It is an estimate with a typical ±3–4 % error versus clinical methods like DEXA. Its value is the trend: measuring the same way every time shows whether your body fat is going up or down across weeks.
How do I take the measurements correctly?+
Neck: just below the Adam's apple, without squeezing. Waist: at navel height, relaxed. Hip (women): at the widest point. Use a flexible tape and always measure under the same conditions, ideally in the morning.
How is this different from BMI?+
BMI only relates weight and height and cannot tell fat from muscle — a very muscular person can read as 'overweight'. A body-fat estimate is closer to your real body composition, which is why the two measures complement each other.