Body Fat Calculator
Your Measurements
inches
inches
inches
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Body Fat Percentage
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Category
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Fat Mass
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Lean Mass
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Enter values to see the worked formula.
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Uses the U.S. Navy circumference method: for men, 86.010·log10(waist − neck) − 70.041·log10(height) + 36.76; for women, 163.205·log10(waist + hip − neck) − 97.684·log10(height) − 78.387 (all in cm). See also BMI, lean body mass, and BMR.
You enter your gender, body measurements (height, waist, neck, and hip for women), and weight. The tool converts imperial measurements to centimeters if needed, then applies the U.S. Navy circumference method. For men: BF% = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. For women: BF% = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. Fat mass and lean mass are derived from the percentage and your total weight.
The Navy method is typically within 3–4% of results from more precise methods like DEXA scans. It tends to be less accurate for very lean or very obese individuals. For most people, it provides a useful estimate for tracking trends over time.
Measure at the navel (belly button) level, not at the narrowest point. Stand relaxed, don't suck in your stomach, and keep the tape snug but not compressing the skin. Measure in the morning before eating for the most consistent results.
Women typically store more fat around the hips and thighs. The Navy formula accounts for this sex-specific fat distribution pattern by including hip circumference, which improves accuracy for women compared to using waist and neck alone.
This depends on your goals. For general health, 10–20% for men and 18–28% for women is typically considered a healthy range. Athletes may be lower. Going below essential fat levels (under 6% for men, 14% for women) can be dangerous. Consult a healthcare provider for personalized guidance.
Body fat percentage gives a more complete picture than BMI because it distinguishes between fat and lean mass. BMI can classify muscular individuals as overweight. However, BMI is simpler to measure and is still useful as a general screening tool.
Estimate only. Results reflect your inputs and standard formulas — they are not financial, tax, legal, health, or investment advice. Verify important decisions with a qualified professional.