Skinfold Body Fat Calculator

Skinfold assessment estimates body composition from the thickness of pinched skin and subcutaneous fat at standardized anatomical sites. A trained tester uses calipers to apply consistent pressure, records measurements in millimeters, and enters the site total into a population-derived equation. This calculator implements the Jackson-Pollock three-site equations, which first estimate body density and then use the Siri equation to convert density into body fat percentage. The male equation uses chest, abdomen, and thigh measurements. The female equation uses triceps, suprailiac, and thigh measurements. Both equations also include age. After the three measurements are summed, sex-specific coefficients estimate body density; body fat is then calculated as 495 divided by density minus 450. These labels describe the original equation groups and are not a statement about gender identity. Choose the equation whose reference population and measurement sites are appropriate for the person being assessed. Technique is the largest practical source of error. Identify each landmark carefully, grasp a double fold of skin and fat without underlying muscle, place the caliper about one centimeter from the fingers, and wait briefly before reading. Take at least two measurements at each site, rotating through sites rather than repeating one immediately. If readings differ substantially, repeat them and use a consistent protocol. Measure on the same side of the body and under similar hydration, exercise, and time-of-day conditions when tracking change. A skinfold result is an estimate, not a direct measurement of total body fat. Equations perform best in populations similar to the samples used to develop them and can be less accurate at the extremes of age, muscularity, or adiposity. Different methods, including seven-site equations, bioelectrical impedance, air displacement, and DXA, should not be expected to give identical values. For progress tracking, consistency of tester, caliper, sites, and equation is usually more useful than comparing isolated results from different methods. Do not use this output to diagnose a health condition or prescribe nutrition. Discuss body-composition concerns with a qualified health or fitness professional.