Estimated body fat
This calculator estimates your body fat percentage from a few simple tape-measure readings using the U.S. Navy circumference method. It is a quick, no-equipment way to get a number you can track over time, without a caliper, scale, or body scan.
The Navy method relies on the fact that fat tends to gather around the waist, so the gap between your waist and neck measurements predicts body fat fairly well. For men it uses height, neck, and waist. For women it adds the hip measurement, because fat distribution differs. Enter your numbers in centimetres or inches and the result updates instantly, along with a category from essential fat through above average.
Body fat below a healthy floor is not better — some fat is essential. Fitness ranges sit around 14 to 17 percent for men and 21 to 24 percent for women, with athletes lower. A single reading matters less than the trend, so measure under the same conditions each time, ideally in the morning, to see real change rather than daily noise.
How does the U.S. Navy method work?
It estimates body fat from a few tape-measure readings — height, neck, and waist for men, plus hips for women — instead of a skinfold caliper or scan. The measurements feed a formula based on the relationship between waist size and body fat.
How accurate is it?
For most people it lands within a few percentage points of a clinical reading, which is good enough to track changes over time. It is less reliable for very lean athletes or anyone with an unusual build, so treat it as a guide, not a diagnosis.
Where exactly do I measure?
Measure the neck just below the larynx, the waist at the navel for men and at the narrowest point for women, and the hips at the widest point. Keep the tape level and snug without compressing the skin.
What is a healthy body fat percentage?
Common fitness ranges are about 14 to 17 percent for men and 21 to 24 percent for women, with athletes lower. Essential fat sits near 2 to 5 percent for men and 10 to 13 percent for women. Healthy ranges vary by age and goals.
Last reviewed June 2026. Uses the U.S. Navy circumference method. For general guidance, not medical advice.