Sumyard

Body fat estimate

Explore an adult circumference-based body-fat estimate and its limitations.

Jump to result

Historical Navy circumference equations, not current service eligibility rules. Adult educational estimate only; no fitness or health category is assigned.

Your inputs

Updates as you type

circumference-based body fat estimate

17%

A rough measurement model; not a diagnosis or a measured body-fat percentage.

Calculations happen in your browser. Saving is optional.

How to use this tool

Measure height, neck and the stated abdomen/waist site with a level, non-compressing tape.

Choose the equation coefficient and include hip circumference for the female equation. Read the population and measurement limits with the estimate.

Male: 86.010 log10(abdomen−neck)−70.041 log10(height)+36.77; female: 163.205 log10(waist+hip−neck)−97.684 log10(height)−78.387; all inputs in inches

Worked example

17% · circumference-based body fat estimate

Fixed example using the settings below. Monetary examples use USD; dates and times use their stated reference values. This example stays unchanged when you edit your calculation.

Example inputs
  • Sex coefficient used by the published equation: Male coefficient
  • Adult age (years): 30
  • Height (cm): 175
  • Abdomen / waist circumference (cm): 85
  • Neck circumference (cm): 38
  • Hip circumference, female equation (cm): 95

Method illustration: With the male coefficient, 175 cm height, 85 cm abdomen and 38 cm neck gives approximately 17.5%.

Assumptions and limits

  • Historical Navy circumference equations, not current service eligibility rules. Adult educational estimate only; no fitness or health category is assigned.
  • Measure upright, with a level tape without compressing skin. Male abdomen is at the navel; female waist uses the natural waist and hip the widest buttock circumference. Neck is below the larynx.
  • The method has individual error and may be unsuitable with pregnancy, edema, atypical body composition or measurements outside its development population.

Method reference: NOAA commissioned corps body-composition equations

Check or report a result

Check the units, selected calculation and assumptions first. Compare the fixed example above with your inputs to identify what changed.

Report a calculation issue with the page address, hypothetical inputs, result displayed and result expected. Do not include passwords, bank details or other private information.