What this estimate measures

The circumference method estimates body fat from relationships among height, neck, waist, and—when the female formula is selected—hip measurements. It is a screening calculation, not a direct measurement of fat mass. The same unit must be used for every measurement because the formula depends on their relative scale.

How to take consistent measurements

Use a flexible tape that lies flat without compressing the skin. Measure height without shoes. Keep the neck tape level, take the waist measurement at the location required by the protocol, and measure hips around the widest point when needed. Repeat each measurement and use a consistent technique, time, and posture when tracking changes.

Why results can differ

Hydration, tape placement, breathing, body shape, age, training status, and the population used to develop an equation can all affect accuracy. Other methods—including skinfolds, air displacement, bioelectrical impedance, and DXA—use different assumptions and can return different values for the same person.

For adults only. This result is an approximate educational estimate and is not a diagnosis, fitness clearance, or substitute for assessment by a qualified health professional. Do not use it to guide extreme dieting or medical treatment.