Body Fat Calculator
Estimate body fat % using the Navy method.
About this tool
The Body Fat Calculator estimates your body fat percentage using the US Navy circumference method - a validated approach that requires only a tape measure. It also calculates your lean mass and places your body fat in a standard fitness category.
How it works
- Select your sex.
- Enter your height, neck circumference, and waist circumference (and hip circumference for women).
- Click Calculate to see your estimated body fat % and lean mass.
- Compare your result to the standard fitness category ranges.
Example use cases
- Fitness goal tracking: A man with a 34" waist, 15" neck, and 5'10" height gets an estimated body fat of ~17%, placing him in the 'fitness' category.
- Before/after comparison: Take measurements monthly to track body fat trends without needing expensive lab equipment.
Frequently asked questions
Where do I measure my waist?
For men, measure at the navel. For women, measure at the narrowest point of the torso. Measure at the end of a normal exhale.
How accurate is the Navy method?
Studies show an average error of ±3-4% compared to hydrostatic weighing or DEXA. It is accurate enough for tracking trends but not for clinical precision.