Body Fat Estimator (Navy Method)
Estimate body-fat percentage from tape measurements using the U.S. Navy formula — no calipers needed.
Body fat from a tape measure
The U.S. Navy method estimates body-fat percentage from a few circumference measurements instead of calipers or a scan. It works because fat distributes predictably around the neck, waist, and hips relative to height, and a logarithmic formula turns those measurements into a percentage.
Men need neck, waist, and height; women add a hip measurement, since fat patterning differs. Measure with a snug, level tape at the same time of day, and the result usually falls within three to four percent of a lab scan — accurate enough to track progress.
Accurate and private
The formula runs live in your browser as you type, so none of your measurements are uploaded or stored anywhere.
Frequently Asked Questions
What is the U.S. Navy body-fat method?
It estimates body-fat percentage from tape measurements — neck, waist, and (for women) hips, along with height — using a logarithmic formula. It needs no calipers, which is why the Navy adopted it.
How accurate is it?
For most people it lands within about 3–4% of a DEXA scan, good enough to track a trend over time. Measure consistently, at the same time of day, for meaningful comparisons.
Where do I measure?
Neck below the larynx, waist at the navel (men) or the narrowest point (women), and hips at the widest point (women). Keep the tape snug and level.
Is my data private?
Yes. The estimate is computed in your browser and none of your measurements are uploaded.
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