Health
Estimate adult body fat percentage with the US Navy circumference method using height, neck, waist, and hip measurements.
Calculate an estimated body fat percentage, fat mass, and lean mass with metric or US measurements.
This adult body fat estimate is for general information, not diagnosis or an official military assessment. Tape measurements and body-fat equations have meaningful error.
Use a flexible tape on bare skin or thin clothing. Stand relaxed, keep the tape horizontal, and take each measurement two or three times. Use the average when repeated measurements differ.
For men, measure the neck below the larynx and the abdomen at navel level. For women, measure the neck, the natural waist, and the widest part of the hips.
General reference charts often use different ranges for men and women. They can describe essential-fat, athletic, fitness, average, and higher ranges, but the cutoffs are not a medical diagnosis and can vary by source, age, and population.
The percentage is most useful as a repeatable estimate. A trend measured the same way is usually more informative than comparing one result with a rigid category.
BMI uses only height and weight, so muscular and less muscular people can have the same BMI. A circumference body fat calculator adds information about body shape, but it is still an indirect estimate.
For a fuller picture, compare this result with BMI, waist circumference, health history, and professional measurements when appropriate.
The equation was designed for adult circumference screening and may be less suitable for children, pregnancy, highly muscular builds, or body shapes far from the populations used to develop it.
Official military body-composition assessments also specify exact tape placement and rounding. Do not use this page as proof of eligibility or as a substitute for an official assessment.
US Navy circumference estimate: men use abdomen minus neck; women use waist plus hip minus neck. Measurements are converted to inches before applying the logarithmic equation.
A 175 cm man with a 38 cm neck and 86 cm waist has an estimated body fat percentage of about 18%.
It uses the US Navy circumference equation. Men enter height, neck, and waist; women also enter hip circumference.
For this method, men measure the abdomen at navel level. Women measure the natural waist at its narrowest point. Keep the tape level and snug without compressing the skin.
No. Official assessments use prescribed measurement and rounding procedures. This calculator is a continuous estimate for general use.
No. BMI compares weight with height. This method uses body circumferences to estimate body fat percentage, but it still does not directly measure fat tissue.
Yes. Choose metric units. The calculator converts the circumference measurements to inches internally because the equation constants are defined for inches.
Results can change with tape placement, breathing, hydration, and the equation's limits. Compare measurements taken under similar conditions and do not treat small changes as exact.