Body Fat Calculator
Calculate your body fat percentage using the US Navy method. Enter measurements to get your body fat % and health category.
About This Tool
The Body Fat Calculator estimates your body fat percentage using the U.S. Navy circumference method. By measuring specific body parts with a tape measure, you can get a reasonable estimate of your body composition without expensive equipment like DEXA scans or hydrostatic weighing.
How to Use
- Select your gender (male or female).
- Choose your preferred unit system (metric cm or imperial inches).
- Enter your height, waist circumference, and neck circumference. For females, also enter hip circumference.
- Click the Calculate button.
- View your body fat percentage and health category (underfat, healthy, overfat, or obese).
Frequently Asked Questions
What is the US Navy body fat calculation method?
The US Navy body fat formula estimates body fat percentage using circumference measurements (waist, neck, hip) and height. It provides a reasonably accurate estimate without expensive equipment like calipers or DEXA scanners, making it widely used for fitness assessments.
Where should I measure my waist circumference?
Measure your waist at the widest point around the abdomen, typically at navel level. Keep the tape snug but not compressing the skin, and measure while exhaling naturally. For men, measure at navel height; for women, measure at the narrowest point of the torso.
What is a healthy body fat percentage?
Healthy body fat ranges differ by gender. For men, 6–24% is considered healthy, while for women, 16–31% is normal. Essential fat is 2–5% for men and 10–13% for women — dropping below these levels can cause health issues.
How accurate is this calculator?
The US Navy formula is generally accurate within ±3–4% compared to DEXA scans. Accuracy may decrease for individuals with extreme body types or very high muscle mass. For precise measurements, consider professional DEXA or hydrostatic weighing.
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How It's Calculated
The U.S. Navy method uses circumference measurements and height to estimate body fat percentage. For men: Body Fat % = 86.010 × log₁₀(abdomen − neck) − 70.041 × log₁₀(height) + 36.76. For women: Body Fat % = 163.205 × log₁₀(waist + hip − neck) − 97.684 × log₁₀(height) − 78.387.
All measurements should be in centimeters (or inches, then converted). Abdomen/waist is measured at the navel level, the neck at its narrowest point just below the larynx, and hips (women only) at the widest point.
The American Council on Exercise (ACE) body fat categories are: Essential fat (Men 2–5%, Women 10–13%), Athletes (Men 6–13%, Women 14–20%), Fitness (Men 14–17%, Women 21–24%), Average (Men 18–24%, Women 25–31%), Obese (Men 25%+, Women 32%+). This method has a typical accuracy of ±3–4% compared to DEXA scans.
⚠️ Disclaimer
Body fat estimates from circumference measurements are approximations with a typical error margin of ±3–4%. Results may be less accurate for very lean or very overweight individuals. For precise body composition analysis, consult a healthcare professional or use clinical-grade equipment.