Calculate your body fat percentage using the widely-used US Navy circumference method — no special equipment needed.
Reasonably accurate for most people (within a few percentage points) and widely used since it requires no special equipment, though less precise than DEXA scans or hydrostatic weighing.
Height, neck circumference, and waist circumference for men. Women additionally need hip circumference.
Typically at the navel level, measured while standing relaxed, not pulled in tight.
This tool estimates body fat percentage using the US Navy circumference method, a formula developed by the US Navy as a practical, equipment-free way to estimate body fat using just a measuring tape and a few body circumference measurements.
Unlike BMI, which only considers height and weight, the Navy method uses circumference measurements — neck, waist, and (for women) hips — combined with height, in a logarithmic formula that correlates reasonably well with more precise body fat measurement techniques. This makes it more representative of actual body composition than weight-based measures alone, since it accounts for where body mass is distributed rather than just total weight.
General ranges (these vary somewhat by source and age): for men, roughly 6-13% is considered athletic, 14-17% fitness, 18-24% average, and 25%+ is generally categorized as obese. For women, ranges run higher due to essential fat differences: roughly 14-20% athletic, 21-24% fitness, 25-31% average, and 32%+ generally categorized as obese.
All calculations run directly in your browser — your measurements are never sent to a server.