ToolWren › Body Fat

Body Fat Calculator

Estimate your body fat percentage using the U.S. Navy tape-measure method, based on a few body measurements.

100% client-side · nothing is uploaded

Loading tool…

How to use the Body Fat

Fill in each input field with your own numbers.
Results calculate automatically and update as you change any value.
Read the result cards below the inputs for the full breakdown.
Adjust any field to explore different scenarios instantly.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About Body Fat

The U.S. Navy method

This widely used method estimates body fat from neck, waist (and hip for women) and height measurements — no special equipment beyond a tape measure.

Why body fat, not just weight

Body fat percentage describes composition better than weight or BMI alone, distinguishing muscle from fat.

Frequently asked questions

How accurate is the Navy method?

It is a reasonable estimate but less precise than DEXA or calipers; measure carefully.

What measurements do I need?

Height, neck and waist (men); plus hip (women), all in centimeters.

Is body fat better than BMI?

It reflects composition better, since BMI cannot tell muscle from fat.