Body Fat Calculator — US Navy Circumference Method
Estimate body fat percentage using the US Navy tape-measure method. Needs only waist, neck (and hip, for women), and height. Metric or imperial.
Runs 100% in your browser — nothing is uploaded.
US Navy circumference method. Typical error ±3–4% compared to DEXA scans. Measure at the narrowest part of the waist for men, or the natural waist for women; hip at the widest point; neck below the larynx.
Frequently asked
Typical error is ±3–4% body fat compared to gold-standard DEXA scans. Better than BMI at distinguishing muscle from fat, but less accurate than skinfold calipers or bioimpedance for individual tracking.
Neck: just below the larynx (Adam's apple), tape roughly horizontal. Waist: for men, at the navel; for women, at the natural waist (narrowest point). Hip (women only): at the widest part of the hips/buttocks. Keep the tape snug but not compressing skin.
The Navy formula was fit against different anthropometric patterns for each sex. Women's bodies deposit fat more variably around the hips, so hip circumference is the extra input the female equation needs.
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