How the body fat calculator works
This tool estimates body fat percentage using the US Navy circumference method, which relies on a few tape measurements rather than special equipment. Enter your height, neck, and waist, plus hip for women, and the tool applies the Navy formula and estimates your fat mass and lean mass from your weight.
Taking good measurements
Measure with a flexible tape held snug but not tight, without compressing the skin. Measure the neck below the larynx, the waist at the navel for men and at the narrowest point for women, and the hips at the widest point. Stand relaxed and breathe normally. Small differences in placement change the result, so measure a few times and average.
How accurate it is
The Navy method is convenient and reasonably consistent for tracking change over time, but it is an estimate, not a precise measurement. Methods like DEXA scans or hydrostatic weighing are far more accurate. Use this to spot trends rather than to fixate on a single exact number, since tape error alone can shift the result by a few percent.
Understanding the ranges
Body fat ranges differ by sex because women carry more essential fat for healthy physiological function. The range label here is a general reference, not a target or a judgment. A wide spread of body fat levels is compatible with good health, and what is right for you depends on your goals, genetics, and overall picture. This tool is general information, not medical advice.
Frequently asked questions
How is body fat estimated from measurements? The US Navy formula uses height and circumference measurements to estimate percentage body fat.
Is the Navy method accurate? It is a reasonable estimate good for tracking trends, but less precise than a DEXA scan.
Why do women enter hip measurement? The formula for women includes the hip circumference to improve the estimate.
Related calculators: BMI, BMR, Ideal Weight.