Navy Body Fat Calculator
Estimate your body fat percentage with the US Navy circumference (tape test) method.
Runs entirely in your browser. Your measurements are never uploaded.
How to use this tool
Pick Male or Female, then enter your measurements in centimeters. Measure your height standing straight. For the neck, wrap a tape just below the larynx (Adam's apple) and keep it level. For the waist, measure at the navel for men and at the narrowest point for women. Women also enter the hip measurement at the widest point. Press Calculate to see your estimated body fat percentage and the matching category.
The formula: body fat percentage navy method
The US Navy circumference body fat method uses base-10 logarithms of your tape measurements together with your height. The formulas below use centimeters.
BF% = 495 / (1.0324 - 0.19077 × log10(waist - neck) + 0.15456 × log10(height)) - 450
Women:
BF% = 495 / (1.29579 - 0.35004 × log10(waist + hip - neck) + 0.22100 × log10(height)) - 450
Because the method relies only on a tape measure, it is sometimes called the navy tape test. It is a quick estimate of circumference body fat and does not require calipers, a scale, or any lab equipment.
A real example
Take a man who is 178 cm tall with a 38 cm neck and an 85 cm waist. The waist minus neck is 47 cm, log10(47) is about 1.6721, and log10(178) is about 2.2504. Plugging in: 495 / (1.0324 - 0.19077 × 1.6721 + 0.15456 × 2.2504) - 450, which works out to roughly 18.4% body fat. That places him in the "Fitness" range for men.
Common questions
What is the Navy body fat calculator?
It is a tool that estimates your body fat percentage from simple tape measurements (height, neck, waist, and hip for women) using formulas developed by the US Navy. It needs no scale or calipers.
How accurate is the navy tape test?
For most people it lands within a few percentage points of more advanced methods like DEXA scans. Accuracy depends on careful, level measurements. It is an estimate, not a clinical result.
Why do women need a hip measurement?
Body fat distribution differs between sexes, so the women's formula adds the hip circumference to better reflect typical fat patterns. Men's bodies are estimated well without it.
Should I measure in inches instead?
This calculator uses centimeters because the standard log10 formulas are written for centimeters. If you measured in inches, multiply by 2.54 to convert before entering your numbers.
What do the body fat categories mean?
They are general fitness ranges (essential fat, athletes, fitness, average, and above average) that differ for men and women. They give context but are not a medical diagnosis.
Note: This calculator gives an estimate for educational use only and is not medical advice. Talk to a healthcare professional for any health decisions.