Estimate your body fat percentage using the U.S. Navy method — just a tape measure, no calipers or expensive scans needed.
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The U.S. Navy method has an accuracy of ±3–4%. For more precise measurements, consider DEXA scans or hydrostatic weighing.
The U.S. Navy body fat formula uses circumference measurements and height to estimate body fat percentage. It was developed by Hodgdon and Beckett at the Naval Health Research Center and is used by all branches of the U.S. military for fitness assessments.
For men, the formula uses neck, waist, and height measurements. For women, it adds hip circumference. The calculation uses logarithmic equations that correlate closely with underwater weighing results — the traditional gold standard for body composition.
Body fat classifications vary by sex because women naturally carry more essential fat for reproductive and hormonal functions. Essential fat is the minimum needed for normal physiological function — below this level, health problems become likely.
For general health, most men should aim for 10–20% and most women for 18–28%. Athletes and competitive bodybuilders operate at lower ranges, but sustaining very low body fat long-term can impair immune function and hormone production.
The Navy method is accurate within ±3–4% compared to DEXA scans. It's most accurate for people in the normal-to-moderately-overweight range. For very lean or very overweight individuals, it may be less precise.
Measure at the level of your navel (belly button), not at the narrowest point of your torso. Keep the tape horizontal and snug — not compressing the skin. Measure on bare skin for best accuracy.
BMI only considers height and weight, so it can't distinguish between muscle and fat. A muscular athlete and an overweight sedentary person can have the same BMI but vastly different body fat levels. Body fat percentage gives a more accurate picture of body composition.