Free Clinical Tool
Body Fat % Calculator
Estimate body fat percentage using the U.S. Navy circumference method. Get body composition breakdown including lean mass, fat mass, and fitness category.
Body fat percentage provides a more meaningful assessment of body composition than BMI alone. While BMI uses only height and weight, body fat percentage distinguishes between fat mass and lean mass — critical information for physical therapists designing rehabilitation programs, health coaches setting body composition goals, and chiropractors assessing overall wellness. The U.S. Navy method uses simple circumference measurements (neck, waist, and hip for women) to estimate body fat without requiring expensive equipment like DEXA scans or calipers. While not as precise as laboratory methods, it provides a reliable, repeatable estimate that practitioners can perform with just a measuring tape.
How to Use This Calculator
Select the patient's sex and preferred unit system. Measure and enter neck circumference, waist circumference (at the narrowest point), and hip circumference (women only, at the widest point). Enter the patient's height. The calculator will display body fat percentage, lean mass percentage, and the corresponding fitness category.
Formula & Method
U.S. Navy Method — Male: %BF = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. Female: %BF = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. All measurements in centimeters. Categories — Essential Fat: 2-5% (M) / 10-13% (F), Athletes: 6-13% (M) / 14-20% (F), Fitness: 14-17% (M) / 21-24% (F), Average: 18-24% (M) / 25-31% (F), Obese: 25%+ (M) / 32%+ (F).
Disclaimer
The U.S. Navy method provides an estimate based on circumference measurements and may not be accurate for all body types, particularly very muscular individuals or those with unusual body proportions. For precise body composition analysis, consider referring to facilities with DEXA or hydrostatic testing.
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