Body Fat Percentage Calculator
Estimate your body fat percentage with the U.S. Navy method, based on your height, neck, waist (and hip for women) measurements. No measurements are sent to a server; everything is computed in your browser.
How It Works
Unlike BMI, which doesn't distinguish fat mass from muscle mass, the U.S. Navy method estimates body composition from simple tape measurements: neck, waist, and, for women, hips. Developed for the U.S. military, it remains an accessible method without a bioelectrical impedance scale or DEXA scan.
Where and how should I accurately measure the waist?
The waist is usually measured at the navel level, breathing out naturally, without sucking in your stomach. Neck circumference is taken just below the Adam's apple. An inaccurate measurement of a few centimeters can noticeably change the result, so take your measurements with a flexible tape measure, flat against the skin.
Is this method as reliable as a DEXA scan?
No, the U.S. Navy method remains an estimate based on statistical regression, with a margin of error of around 3 to 4 percentage points compared to reference methods such as DEXA scan or hydrostatic weighing. It is nevertheless recognized as reliable enough to track changes over time, as long as measurements are taken consistently.
Your measurements stay strictly private: no data is transmitted or stored outside your device.