Body Fat Calculator
Estimate body fat percentage using the US Navy tape-measure method.
Assumptions used in this calculation
- Formula: Uses the US Navy circumference method, a validated tape-measure estimate rather than a direct body-composition measurement.
About this calculator
Body fat percentage matters more than scale weight for judging fitness progress, but the accurate ways to measure it, DEXA scans, hydrostatic weighing, skinfold calipers in trained hands, are expensive, inconvenient, or require practice to use correctly. This calculator uses the US Navy circumference method instead: a validated formula that only needs a tape measure. Enter height plus neck and waist circumference (men), or height plus neck, waist and hip circumference (women), and it applies a logarithmic formula, different for each sex, to estimate body fat percentage and place it into a category from essential fat to obese. Because it relies on log-transformed circumference ratios rather than a linear formula, the math isn't something to do reliably by hand or with a rough approximation. The result won't match a DEXA scan exactly, but it's typically within a few percentage points and is far more accessible for tracking trends over time than any lab-based method.
Worked example
Male, 180 cm, neck 38 cm, waist 85 cm
Result: Body fat ≈ 16.1% (Fitness)
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