What this calculator does
Body fat percentage says more about body composition than weight alone. The US Navy method estimates it from circumference measurements and is a practical alternative to scales and mirrors.
This calculator shows body fat, fat mass, lean mass and a reference range. For greater precision, DEXA, calipers or professional bioimpedance are better options.
US Navy formula
Men: 495 ÷ (1.0324 − 0.19077 × log(waist − neck) + 0.15456 × log(height)) − 450 The female formula also includes hip circumference. Measurements are in centimetres; the formula is sensitive to measurement technique.
How this calculator works
- 01
Measure circumferences
Measure neck, waist and, for women, hips without compressing the skin.
- 02
Enter body data
Height, weight and sex are combined with the measurements.
- 03
Read body composition
Compare body fat, fat mass and lean mass with the reference range.
Frequently asked questions
How accurate is the US Navy method?
With careful measurement, it is often within a few percentage points. Body shape, measurement position and hydration can affect the result.
What is a healthy body fat percentage?
Reference ranges are roughly 10–20% for men and 18–28% for women. Athletes and older adults may sit outside these ranges.
Why does waist circumference matter?
Visceral fat around the organs carries more health risk than subcutaneous fat. Waist-to-height should generally stay below 0.5.
Data basis: 2026 · Annual constants live in structured JSON files and are updated once a year.
Results are unverified model calculations and do not replace tax, legal or financial advice.