Estimate your body fat percentage with the US Navy circumference method — just a tape measure required, no calipers or scans.
Developed at the Naval Health Research Center, the method estimates body density from circumference measurements and height, then converts it to a fat percentage:
Men: 495 ÷ (1.0324 − 0.19077×log10(waist − neck) + 0.15456×log10(height)) − 450
Women: 495 ÷ (1.29579 − 0.35004×log10(waist + hip − neck) + 0.22100×log10(height)) − 450
Against DEXA scans it is accurate to about ±3-4% for most body types — comparable to consumer body-fat scales and far better than BMI at describing composition.
Consistency matters more than precision. Measure at the same time of day, tape snug but not compressing the skin:
Track your trend over weeks rather than reacting to single readings. Pair this with the calorie calculator to plan a cut or bulk, or the ideal weight calculator for a target range.
The US Navy method estimates body fat from circumference measurements: neck and waist for men, plus hips for women, combined with height in a logarithmic formula. It is accurate to within 3-4% for most people.
For men, 14-24% is average and 6-13% is athletic. For women, 21-31% is average and 14-20% is athletic. Women naturally carry more essential fat than men.
Measure your waist at the navel, relaxed, without pulling the tape tight. Measure your neck just below the larynx, keeping the tape slightly sloped downward to the front. Women measure hips at the widest point.
They're comparable. Bio-impedance scales fluctuate with hydration, while the tape method depends on measurement technique. For both, the trend over time is far more meaningful than any single reading.