About this body fat percentage calculator
Estimate body fat percentage using the U.S. Navy circumference method, which uses neck, waist, and, for women, hip measurements alongside height, rather than a scale that can't distinguish fat from muscle. Enter your measurements in centimeters, taken with a flexible tape at the points that method specifies, to see an estimated body fat percentage and a general category from essential fat through above average. This method is a widely used field estimate, not a laboratory-grade measurement like a DEXA scan.
How it works
For men: %BF = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450. For women: %BF = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450. All measurements are in centimeters.
Try these examples
Male: height 175 cm, waist 85 cm, neck 38 cm
Body fat 16.94% · Fitness
Female: height 165 cm, waist 75 cm, hip 100 cm, neck 32 cm
Body fat 29.93% · Average
Limitations & privacy
Accuracy depends heavily on precise, consistent tape placement and is generally less accurate for very lean or very heavy individuals than lab methods like DEXA or hydrostatic weighing. This is an estimate for general awareness, not a medical or athletic-grade measurement.
Inputs and results stay in this browser. Only tool identifiers are stored for your recently used tools. You can clear that history from the directory.
A few good questions
Where exactly do I measure my waist and neck?
Measure the neck just below the larynx, and the waist at the navel for men or at the narrowest point for women, keeping the tape snug but not compressing the skin.
Why does the formula need a hip measurement for women only?
The U.S. Navy method uses separate validated formulas for each sex; the women's version was derived using hip circumference as an additional predictor, while the men's version was not.
How does this compare to a DEXA scan?
DEXA scans directly measure fat, lean, and bone mass and are considered a gold standard. Tape-based estimates like this one are a convenient approximation, typically within a few percentage points for most body types.
Updated September 19, 2026