How the US Navy method works
Instead of pinching skinfolds or scanning the body, this method estimates body fat from a few tape-measure circumferences and your height. The waist and neck (plus hips for women) capture where fat tends to accumulate, and a logarithmic formula converts those measurements into a percentage.
From that percentage and your body weight, the calculator splits your weight into fat mass — the kilograms attributable to body fat — and lean mass, which covers muscle, bone, organs and water.
Reading your result
The headline percentage places you in a category from essential fat through to obese, using ranges that differ between men and women because women carry more essential fat.
The pie chart shows the proportion of your weight that is fat versus everything else (lean mass). It is a useful complement to BMI, which cannot tell muscle and fat apart.
Getting reliable measurements
Tape-measure accuracy makes or breaks this estimate, so measure carefully:
- Use a flexible tape held snug but not compressing the skin.
- Measure the waist at the navel and the neck just below the larynx.
- Keep the tape level all the way around and relax — do not suck in.
- Take each measurement two or three times and use the average.
Accuracy and health note
Circumference-based estimates are convenient but approximate, and they can read high or low for very lean or very muscular bodies. They are not a clinical diagnosis. For decisions about your health, rely on a qualified professional and more precise methods such as DEXA, and consult a doctor before acting on any single number.
Formula
male: 495/(1.0324 − 0.19077·log₁₀(waist−neck) + 0.15456·log₁₀(height)) − 450; female: 495/(1.29579 − 0.35004·log₁₀(waist+hip−neck) + 0.22100·log₁₀(height)) − 450Frequently asked questions
- How accurate is the Navy method?
- It is typically within a few percent of skinfold testing for most people, but circumference-based estimates can be off for very lean or very muscular bodies.