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Calculators
Estimate body fat percentage using the US Navy circumference method (neck, waist, hip measurements). Shows fat mass, lean mass, and fitness category for both men and women.
Follow these simple steps to get instant, accurate results directly in your browser:
Choose biological sex and select metric (cm) or imperial (inches).
Measure neck circumference, waist (at navel), and hips (for women at widest point).
Inspect your estimated body fat percentage, lean mass, fat mass, and fitness category.
The Body Fat Calculator estimates your body fat percentage, fat mass, and lean muscle mass using the official U.S. Navy Circumference Method.
While scale weight alone cannot differentiate between dense muscle mass, bone density, and adipose fat tissue, the U.S. Navy formula utilizes circumferences of the neck, waist, and hips (for females) combined with height to estimate body composition with high accuracy (correlating closely with hydrostatic weighing and DEXA scans).
All calculations run in client-side memory, allowing you to track your body composition progress in complete privacy.
Disclaimer: This tool provides general estimates for informational purposes only and does not constitute medical advice. Consult a healthcare professional before making health or fitness decisions.
Men: % Fat = 495 / [1.0324 - 0.19077 * log10(waist - neck) + 0.15456 * log10(height)] - 450
Women: % Fat = 495 / [1.29579 - 0.35004 * log10(waist + hip - neck) + 0.22100 * log10(height)] - 450Logarithmic equations published by the U.S. Naval Health Research Center (Hodgdon and Beckett, 1984).
Male: Height = 180 cm | Neck = 38 cm | Waist = 86 cm Waist - Neck = 48 cm | log10(48) = 1.68124 | log10(180) = 2.25527 Calculated Body Fat = approximately 15.8% (Fitness Category).
Our calculation methodologies adhere to published guidelines from authoritative government agencies and standards bodies:
Uses the validated logarithmic circumference method developed by the Naval Health Research Center.
Shows exact kilograms or pounds of lean muscle versus fat tissue.
Classifies results into Essential Fat, Athletes, Fitness, Average, and Obese.
Your body measurements are never transmitted or stored externally.
Track true fat loss progress during fitness training when scale weight stays constant.
Prepare for military body composition assessments (tape test compliance).
Monitor lean mass retention during contest prep and athletic cut phases.
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