Navy Body Fat Calculator
Calculate body fat percentage, lean tissue weight, and fat mass using the official Department of Defense circumference tape measurement method.
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How the US Navy Body Fat Formula Works
The US Navy circumference tape method is codified in Department of Defense Instruction 1308.3. It estimates body density and adipose percentage from log circumference ratios:
Men Formula (Inches)
%BF = 86.010 × log10(Waist - Neck) - 70.041 × log10(Height) + 36.76
Women Formula (Inches)
%BF = 163.205 × log10(Waist + Hip - Neck) - 97.684 × log10(Height) - 78.387
American Council on Exercise (ACE) Categories
- Essential Fat: 2-5% (Men) | 10-13% (Women)
- Athletes: 6-13% (Men) | 14-20% (Women)
- Fitness: 14-17% (Men) | 21-24% (Women)
- Average: 18-24% (Men) | 25-31% (Women)
- Obese: 25%+ (Men) | 32%+ (Women)
Frequently Asked Questions
How accurate is the Navy tape test compared to DEXA scan?
The US Navy formula correlates strongly with DEXA scans (typical margin of error is within 3% to 4%), provided measurements are taken consistently with a non-elastic spring-loaded vinyl tape measure.
Where exactly should the waist be measured?
For men, measure horizontally across the navel (belly button) while keeping arms at sides after a relaxed exhale. For women, measure at the narrowest point of the natural waist.
Why does the formula include neck circumference?
Neck circumference serves as an anatomical proxy for skeletal muscularity and frame size, preventing muscular lifters with thick necks from being misclassified as overweight.