Measure waist at the narrowest point, neck just below the larynx (Adam's apple). Add your weight to also see estimated fat mass and lean mass.
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Fat mass
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Lean mass
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Category ranges
Know your body fat %? Plug it into the TDEE & Macro Calculator for a more accurate calorie estimate using the Katch-McArdle formula.
The Navy method is an estimate based on circumference measurements, not a direct measurement of body composition (like DEXA or hydrostatic weighing). Use it to track trends over time rather than as an exact number.
How it's calculated
Measure with a flexible tape. Neck just below the larynx; waist at the narrowest point (or navel level); women also measure hips at the widest point.
We apply the U.S. Navy formula. Developed by the Naval Health Research Center, it estimates body fat from the ratio of these circumferences to your height.
You get a percentage and category. Compared against standard ranges (Essential Fat, Athletic, Fitness, Acceptable, Obese) so you know what your number means.
This is a population-based estimation formula, not a clinical body composition test. For a lab-accurate reading, ask about DEXA scans or hydrostatic weighing.
Frequently asked questions
Generally accurate within about 3-4% of more precise methods like DEXA scans for most people, making it one of the better tape-measure-only estimation methods available. It can be less accurate for people with atypical fat distribution or very high muscle mass.
Height, neck circumference, and waist circumference. Women also need a hip circumference measurement. Measure waist at the narrowest point (or at the navel), neck just below the larynx, and hips at the widest point.
The Navy method estimates body fat from the ratio between your waist (and hip, for women) and your neck circumference, using neck size as a rough proxy for frame size. It's not measuring fat in your neck directly.
BMI only uses height and weight, so it can't tell the difference between muscle and fat. Body fat percentage estimates the actual proportion of your weight that's fat versus lean mass.
Enter it into our TDEE & Macro Calculator, which uses the Katch-McArdle formula for a more accurate calorie estimate based on your lean body mass rather than a population average.