Calculate your body fat percentage using the US Navy method
This free body fat calculator estimates your body fat percentage with the US Navy method. Enter your height, weight, neck and waist measurements (and hips if you are female) to see your body fat percentage, fitness category, fat mass and lean mass.
You can use metric (cm and kg) or imperial (inches and pounds). All you need is a tape measure.
With all measurements in centimeters, the formulas are:
Example: a man who is 175 cm tall, weighs 75 kg, with a 38 cm neck and an 80 cm waist has about 12.9% body fat. That is about 9.7 kg of fat mass and 65.3 kg of lean mass, which falls in the Athletic category on this page.
It is an estimate based on body measurements, not a direct measurement. It is often within a few percentage points of lab methods such as a DEXA scan, but it can be off by more for some people. It works best for tracking changes over time when you measure the same way each time.
Use a soft tape measure held snug but not tight. Measure the neck just below the larynx (Adam's apple). Men measure the waist at the navel. Women measure the waist at the narrowest point and the hips at the widest point. Breathe out normally and measure each place twice to check.
Women generally store fat differently from men, so the formula for women also uses hip size. The calculator shows the hip box only when you choose Female.
Healthy ranges depend on age, sex and fitness goals. Men in the 14% to 24% range and women in the 21% to 31% range fall in the fitness to average categories used on this page. Levels that are too low can also be unhealthy, so speak to a healthcare professional about your own target.
BMI only uses height and weight, so it cannot tell muscle from fat. Body fat percentage estimates how much of your weight is fat, which is more informative for people who are very muscular or who are carrying extra fat at a normal weight.
Fat mass is the weight of the fat in your body. Lean mass is everything else, including muscle, bone, organs and water. Fat mass plus lean mass equals your total body weight.
Disclaimer: This is an estimate for general information only and not medical advice. Talk to a healthcare professional about your health and fitness goals.