Body Fat Estimate Calculator
Estimate body-fat percentage from circumference measurements using a Navy/DoD-style logarithmic method with metric or inch inputs.
Estimate body-fat percentage
Use circumference measurements to generate an approximate body-fat percentage. Measurement technique strongly affects the result.
How this body-fat estimate is calculated
The tool uses circumference-based logarithmic equations of the type used in U.S. military body-composition procedures. For the male equation, the key circumference value is waist minus neck. For the female equation, it is waist plus hip minus neck. Height and circumferences are evaluated in inches.
Measurement consistency matters
Small differences in tape location or tension can change the estimate. Official military procedures specify measurement locations and rounding rules; this general-purpose calculator does not reproduce an official fitness assessment. See a current example of circumference methodology in U.S. Coast Guard body-composition guidance: body-composition instruction.
Why this is only an estimate
Circumference equations infer body-fat percentage from external measurements. They can be useful for tracking a consistent personal method over time, but they are not equivalent to DXA, air-displacement plethysmography or other laboratory methods.
Do not use the result as a diagnosis
Body-fat percentage alone does not determine health or athletic performance. If you need a clinically meaningful body-composition assessment, use a qualified professional and an appropriate measurement method.
Improve repeatability before comparing estimates
Circumference-based body fat estimates are sensitive to tape placement and measurement technique. Measure at the same anatomical locations, with the tape level and snug but not compressing tissue, and repeat measurements under similar conditions. Use the calculator to monitor a consistent method over time rather than treating small day-to-day changes as real changes in body composition. For clinical or sport-critical decisions, use a validated assessment method and trained practitioner.