Body Fat Calculator
Estimate your body fat percentage with the US Navy tape method and see your fat mass, lean mass and category.
- The US Navy method is an estimate: it usually differs from laboratory methods (DEXA, hydrostatic weighing) by 3 to 4 percentage points.
- Formulas of Hodgdon and Beckett (US Navy, 1984) adopted by the US Department of Defense in 2002; measurements are converted to inches.
- Not meant for children, teenagers, pregnant women or people with medical conditions.
Related calculators: BMI Calculator · Calorie Calculator · Ideal Weight Calculator
Frequently asked questions about body fat
How accurate is the US Navy method?
For most adults it lands within about 3 to 4 percentage points of laboratory methods. Measure carefully, at the same time of day, and repeat to follow the trend.
Why do women also measure the hips?
Women store more fat around the hips, so the women's formula uses waist plus hip minus neck, while the men's formula uses waist minus neck.
What is lean mass?
Lean mass is everything that is not fat: muscle, bone, organs and water. It is your weight minus the fat mass.
How the body fat calculator works
This calculator estimates your body fat percentage with the US Navy tape method. You enter your sex, height, neck and waist measurements, plus the hip measurement if you are a woman, and your weight. From those numbers it shows the body fat percentage, how much of your weight is fat mass and lean mass, and the American Council on Exercise category that the result falls into. The page uses metric units (centimeters and kilograms) and, in English (US), imperial units (feet, inches and pounds). It is meant for healthy adults. Use it to follow your progress over time, and see also the BMI and Calorie calculators.
The method was published by Hodgdon and Beckett at the Naval Health Research Center in 1984 and adopted by the US Department of Defense in Instruction 1308.3 (2002). With every measure in inches, men use 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76, and women use 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. Fat mass is your weight times the percentage divided by 100, and lean mass is your weight minus the fat mass. The category comes from the American Council on Exercise table shown under the result.
Example: a man 178 cm tall, with a 38 cm neck, an 86 cm waist and a weight of 80 kg, has about 17.3% body fat, which is the fitness category. That means roughly 13.8 kg of fat and 66.2 kg of lean mass. Keep in mind that the method is an estimate that can differ by 3 to 4 percentage points from laboratory methods such as DEXA, and that it is not meant for children, teenagers, pregnant women or people with medical conditions. Measure in the same way each time, and talk to a health professional about the result.