Body Fat Calculator
Estimate body fat % using the US Navy circumference method.
Estimate body fat percentage using the US Navy formula based on neck, waist and (for women) hip circumferences plus height. Shows fat mass and lean mass too.
Common use cases
- Track body composition changes during cutting or bulking phases
- Compare to BMI for a more nuanced fitness assessment
- Set realistic body composition goals based on athletic targets
- Re-measure quarterly without lab equipment
Frequently asked questions
How accurate is the US Navy method?▾
Within roughly ±3% for most adults. DEXA and hydrostatic weighing are more accurate but expensive.
Why are women's measurements different?▾
The formula adds hip circumference because women carry more body fat in the lower body, which the neck and waist alone don't capture.
Does it work for athletes?▾
Less reliable for very muscular or very lean individuals — bodybuilders may show falsely low or skewed values.