🏃 Body Fat Percentage Calculator

Estimate your body fat % using the U.S. Navy circumference method

Estimated Body Fat %
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Estimated Lean Mass %
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Body Fat Percentage Calculator — U.S. Navy Method

Body fat percentage gives a much more accurate picture of fitness and health than weight or BMI alone, since it directly estimates the proportion of fat vs lean mass (muscle, bone, organs). This calculator uses the U.S. Navy circumference method, a tape-measurement formula validated for reasonable accuracy without expensive equipment.

Why Body Fat % Matters More Than BMI

BMI can't distinguish between muscle and fat — a muscular athlete and someone with low muscle/high fat can have the identical BMI despite very different health profiles. Body fat percentage directly measures the metric that actually matters for health risk assessment.

Healthy Body Fat Ranges

For men: Essential fat 2-5%, Athletes 6-13%, Fitness 14-17%, Average 18-24%, Obese 25%+. For women: Essential fat 10-13%, Athletes 14-20%, Fitness 21-24%, Average 25-31%, Obese 32%+. Women naturally carry more essential fat due to reproductive biology.

Frequently Asked Questions

How accurate is the tape-measurement method? +
It has roughly a 3-4% margin of error compared to gold-standard methods like DEXA scans or hydrostatic weighing. It's accurate enough for tracking progress over time, but treat the absolute number with some caution.
Why does the formula need different inputs for men and women? +
Body fat distribution patterns differ by sex — women typically carry more fat in the hip/thigh region, which is why the female formula includes hip measurement while the male formula doesn't.
What's the difference between body fat % and BMI? +
BMI only uses height and weight, ignoring body composition entirely. Body fat % directly estimates what proportion of your body mass is fat vs lean tissue, making it a more meaningful health indicator, especially for athletic or muscular individuals.