Body fat percentage
No smart scale needed: a tape measure is enough. The US Navy method estimates body fat from 3 measurements.
Tape measurements: waist at navel level, neck below the Adam’s apple, hips at the widest point.
The US Navy method
Developed for the US military, this method estimates body fat from circumferences (neck, waist, hips for women) and height. Accuracy is about ±3% versus reference methods — comparable to consumer smart scales.
Usual benchmarks: “fit” men 14–17%, “fit” women 21–24%. Essential fat is about 3–5% for men and 10–13% for women.
Measuring correctly
Tape horizontal, snug but not tight: neck just below the Adam's apple, waist at navel level (relaxed), hips at the widest point. Measure in the morning for consistency.
FAQ
How reliable is this estimate?
Within about ±3% for most body types — enough to track progress. Extremes (very muscular or severe obesity) are estimated less well.
Why is my BMI normal but my body fat high?
That’s the “skinny fat” profile: normal weight, little muscle. It’s exactly why body fat usefully complements BMI.
Are my measurements stored?
No, nothing is transmitted or saved: the calculation runs in your browser.