Health Formula • Published on July 30, 2026 • Last updated August 09, 2026
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Waist circumference in cm, measured at the navel
Neck circumference in cm, measured below the larynx
Hip circumference in cm at the widest point (women only)
Standing height in cm
The U.S. Navy Method estimates body fat percentage from simple circumference measurements rather than calipers or DEXA scans, using a regression formula developed by Hodgdon & Beckett that predicts body density from waist, neck, hip (for women), and height, then converts that density to a body fat percentage using the Siri equation (the 495/D − 450 term).
The Navy circumference method typically has a margin of error of around 3-4% body fat compared to gold-standard methods like DEXA, making it a reasonably good field estimate but not a clinical-grade measurement.
Neck circumference correlates with upper-body fat distribution and helps the regression normalize for frame size, improving accuracy compared to using waist circumference alone.
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