Skinfold Body Fat Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Body measurements become more useful when the formula behind them is easy to see. Skinfold Body Fat Calculator turns its specific inputs into one focused estimate.

What this calculator does

Skinfold measurements can estimate body density and body-fat percentage when they are taken with consistent technique. This calculator uses four sites rather than relying on body weight alone. Anthropometric equations are convenient because they use simple measurements, but they describe body size or proportion rather than directly measuring tissue composition or health.

How to use it

Enter or select Gender, Age, Method, Bicep measurement, Subscapular measurement, Suprailiac measurement, and Tricep measurement. Use the units offered by the calculator and keep measurements consistent when you plan to compare results over time.

How the calculation works

It sums biceps, triceps, subscapular, and suprailiac skinfolds, applies the age- and sex-specific Durnin–Womersley body-density equation, and converts density to body-fat percentage with the Siri equation: 495 ÷ density − 450.

Example

For the sample values prefilled in this calculator, the primary result is 21.95 % (Durnin–Womersley body fat), 4-site sum is 52 mm, and Body density is 1.0488. This example is there to show how the inputs flow through the implemented equation; replace the sample values with your own measurements before using the result.

How to interpret the result

The output is an estimated body-fat percentage. For progress tracking, consistency of the person taking the measurements and the exact skinfold sites is often more useful than chasing small day-to-day changes.

Limitations and notes

Caliper skill is a major source of error, and the Durnin–Womersley equations may not fit every age, ethnicity, athletic population, or body-fat range. The method selector is currently fixed to the implemented Durnin–Womersley calculation, so selecting it does not switch among alternative skinfold formulas. For repeat measurements, consistency usually matters more than false precision: use the same unit system, the same tape or scale when possible, and the same anatomical landmarks. A small change near a category boundary should be viewed in context rather than treated as a sudden biological change.