Estimate body-fat percentage with the Jackson–Pollock three-site skinfold method. Enter age and three caliper measurements in millimetres. The required sites change with the selected reference sex.
Your skinfold measurements
Your estimate
Caliper skill, site placement, hydration, and the selected equation can materially affect the result. Repeat each site and use the average for better consistency.
How the three-site method works
For men, the traditional three sites are chest, abdomen, and thigh. For women, they are triceps, suprailiac, and thigh. The sum of the three measurements and age are used to estimate body density, which is converted to body-fat percentage with the Siri equation.
How to improve measurement consistency
Measure on the same side of the body, grasp the skinfold firmly, place the caliper about one centimetre below the fingers, and record the reading after one to two seconds. Take at least two readings per site and use their average.
What unit should I enter?
Enter all skinfold measurements in millimetres. Most skinfold calipers display millimetres directly.
Why does this differ from a smart scale?
Smart scales usually estimate body composition from electrical impedance. Skinfold equations use subcutaneous fat measurements, so the methods can produce different results.
Who should not rely on this equation?
The equation may be less representative outside the adult populations used to develop it, including children, pregnancy, very high body fat, or unusual body-composition patterns.