Estimate your body-fat percentage locally from circumference measurements with the U.S. Navy method - plus fat and lean mass.
No. Everything runs in your browser - your file never leaves your device. How this is verifiable
The body-fat percentage tells you more about your body composition than weight alone, because it separates fat from muscle, bone and water. This calculator estimates it from simple circumference measurements with the well-known U.S. Navy method: you measure neck and waist with a tape, for women also the hip, and enter height and weight. From this you get the body-fat percentage as well as the fat mass and lean mass in kilograms derived from it.
The calculation runs entirely locally in your browser, in pure JavaScript - nothing is uploaded and nothing is stored. The U.S. Navy formula uses the logarithm of the circumferences and the height; for men waist and neck go in, for women the hip as well. The fat mass is the percentage times the weight, the lean mass is the rest. Measure all circumferences relaxed and without pulling the tape tight. Change an input and everything updates instantly.
An honest note: this is an estimate from circumference measurements and only as accurate as your measuring. It does not replace medical advice or precise methods such as caliper measurement, a bioimpedance scale or a DEXA scan. Very muscular people, pregnant women or very lean people may get diverging values. Take the figure as a rough reference point, ideally watched over time. How your weight relates to your height is shown by the BMI calculator.
| Input formats | Form inputs (no file) |
|---|---|
| Processing | Locally in your browser (JavaScript) |
| File upload | None |
Limitations: An estimate using the U.S. Navy circumference method; only as accurate as your measuring. It does not replace medical advice or precise methods (caliper, bioimpedance, DEXA). Very muscular, pregnant or very lean people may get diverging values. For the relation of weight and height use the BMI calculator.
No. The calculation runs entirely locally in the browser (pure JavaScript); nothing is sent or stored. With health data in particular, everything stays on your device.
The U.S. Navy method, which estimates the body-fat percentage from the logarithm of circumferences and height. For men neck and waist count, for women the hip as well. The formula was developed in 1984 by Hodgdon and Beckett at the Naval Health Research Center of the U.S. Navy.
It is a rough reference point and only as accurate as your measuring. Caliper, bioimpedance or a DEXA scan are more precise. It does not replace medical advice.
With a tape measure, relaxed and without pulling tight: the neck below the larynx, the waist at navel height, the hip at its widest point.