Body Fat Calculator (U.S. Navy Method).
Neck, waist, hips and height → body fat %, fat mass and lean mass.
Show the formula
Women: 163.205 × log10(waist + hips − neck) − 97.684 × log10(height) − 78.387, with every measurement in inches (your centimetres are divided by 2.54 first).
How it works.
Measure with a tape
Neck just below the larynx. Waist at the navel for men, at the narrowest point for women. Women also measure the hips at the widest part of the buttocks. Keep the tape level and snug on bare skin.
Enter the measurements and height
Use centimetres or inches. The Navy equations work in inches, so centimetre entries are divided by 2.54 first.
Read body fat, fat mass and lean mass
You get the estimated body fat percentage. Add your weight to also see fat mass and lean mass.
FAQ.
What is the U.S. Navy method?
A pair of equations developed at the Naval Health Research Center by Hodgdon and Beckett in 1984 (report 84-11 for men, 84-29 for women) to estimate body fat percentage from height and a few tape measurements, without lab equipment.
What are the formulas?
Men: 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. Women: 163.205 × log10(waist + hips − neck) − 97.684 × log10(height) − 78.387. Every measurement is in inches; centimetres are divided by 2.54 first.
How accurate is it?
It is a regression estimate, so for an individual the result can differ meaningfully from laboratory methods such as DXA or underwater weighing. If you are tracking change over time, measuring the same way at the same time of day matters more than the absolute number.
Why is there no healthy range chart?
We only publish category cut-offs we can trace to a primary source we have checked. Body fat category charts circulate widely but we could not verify one at its source, so the calculator shows the number without labelling it.
What are fat mass and lean mass?
Fat mass is your weight multiplied by the body fat percentage. Lean mass is everything else: muscle, bone, organs and water. The BMR calculator's Katch-McArdle equation uses lean mass through the body fat percentage.
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