Body Fat Calculator: Circumference Method
Estimate adult body fat with height, neck and waist measurements, plus hips for the female equation. Supports centimeters and inches.
Your inputs
Choose the units and assumptions that match your data. Example inputs are illustrative.
Your result
Enter your values, then choose Calculate.
Results are calculated in your browser. Display rounding does not change the underlying calculation.
Calculation breakdown
Method, assumptions and worked example
How it works
The historical circumference equations use inches. Male estimate = 86.010 × log10(abdomen − neck) − 70.041 × log10(height) + 36.76. Female estimate = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. Centimeter inputs are converted to inches before these equations are applied.
Worked example
For the male equation, height 175 cm, abdomen 85 cm and neck 38 cm give approximately 17.01% body fat.
Using the result
Measure standing height without shoes. For the male equation measure abdomen at the navel; for the female equation measure natural waist and the widest hip circumference. Measure the neck below the larynx with the tape snug, not compressing skin. Small measurement differences affect the estimate. This is not a DEXA result, a health diagnosis or an official current military compliance assessment. Implausible outputs are rejected rather than silently clamped.
Frequently asked questions
Why is body weight not requested?
These circumference equations do not use body weight.
Is this an exact body-fat percentage?
No. Measurement technique and differences between people create uncertainty. Use professional assessment when the result affects care.
Method review and references
Formula and content reviewed on 10 October 2026. Worked examples are hypothetical. Methods and assumptions are explained on each page. Health estimates are not clinical measurements; symbolic tools are for entertainment.