Body Fat Calculator — U.S. Navy Method
Estimate your body fat percentage from tape measurements using the U.S. Navy circumference method — metric or imperial. Free, private, 100% in your browser.
🔒 Calculated in your browser — nothing is uploaded. The U.S. Navy method is a rough estimate, not a medical measurement — talk to a healthcare professional for a real assessment.
Estimate body fat from a tape measure
The U.S. Navy circumference method estimates body fat percentage from a few tape measurements — height, neck and waist (plus hip for women) — with no scale or calipers needed. Enter measurements in centimetres or inches and get a percentage and a general fitness category.
An estimate, not a diagnosis
This is a screening estimate, not a medical measurement. Circumference formulas can be off by several points versus a DEXA scan, and body fat is only one signal of health. For a real assessment, talk to a healthcare professional. Your measurements are never uploaded — everything runs in your browser.
Frequently asked questions
How does the U.S. Navy body fat method work?
It uses log-based formulas on your height, neck and waist (and hip for women) circumferences to estimate body fat percentage — no scale required.
How accurate is it?
It is a rough estimate. It tracks trends reasonably but can differ from lab methods like DEXA by several percentage points. Treat it as a guide, not a diagnosis.
Do I measure in cm or inches?
Either — switch units and enter all measurements in the same system. Measure the neck below the larynx and the waist at the navel.