Skinfold Body Fat Calculator
Estimate body fat percentage from 3-site skinfold caliper measurements using the Jackson–Pollock equations and the Siri conversion.
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What this tool does
Estimate body fat percentage from 3-site skinfold caliper measurements using the Jackson–Pollock equations and the Siri conversion. Men: chest, abdomen, thigh. Women: triceps, suprailiac, thigh. Caliper technique strongly affects results; take each site 2–3 times and average. Research equation, not a measurement.
How to use the Skinfold Body Fat Calculator
- Enter or select sex.
- Enter or select age (years).
- Enter or select site 1 skinfold (mm) — chest (men) / triceps (women).
- Enter or select site 2 skinfold (mm) — abdomen (men) / suprailiac (women).
- Enter or select site 3 skinfold (mm) — thigh.
- Read the calculated result; change any measurement to compare alternatives.
Formula
Jackson–Pollock 3-site body density (sex-specific, uses sum of 3 skinfolds and age); body fat % = 495 / density − 450 (Siri)
- sex
- Sex
- age
- Age (years)
- s1
- Site 1 skinfold (mm) — chest (men) / triceps (women)
- s2
- Site 2 skinfold (mm) — abdomen (men) / suprailiac (women)
- s3
- Site 3 skinfold (mm) — thigh
Men: chest, abdomen, thigh. Women: triceps, suprailiac, thigh. Caliper technique strongly affects results; take each site 2–3 times and average. Research equation, not a measurement.
Worked example
For skinfold body fat calculator, the following measurements illustrate the exact method: Sex: male; Age (years): 30; Site 1 skinfold (mm) — chest (men) / triceps (women): 12; Site 2 skinfold (mm) — abdomen (men) / suprailiac (women): 18; Site 3 skinfold (mm) — thigh: 14.
Inputs
- SexMale
- Age (years)30
- Site 1 skinfold (mm) — chest (men) / triceps (women)12
- Site 2 skinfold (mm) — abdomen (men) / suprailiac (women)18
- Site 3 skinfold (mm) — thigh14
Result
- Estimated body fat (%)13.32
- Estimated body density (g/cc)1.07
- Sum of 3 skinfolds (mm)44
Results explained
- Estimated body fat (%)
- Estimated body fat (%) from the formula above. Men: chest, abdomen, thigh. Women: triceps, suprailiac, thigh. Caliper technique strongly affects results; take each site 2–3 times and average. Research equation, not a measurement.
- Estimated body density (g/cc)
- Estimated body density (g/cc) from the formula above. Men: chest, abdomen, thigh. Women: triceps, suprailiac, thigh. Caliper technique strongly affects results; take each site 2–3 times and average. Research equation, not a measurement.
- Sum of 3 skinfolds (mm)
- Sum of 3 skinfolds (mm) from the formula above. Men: chest, abdomen, thigh. Women: triceps, suprailiac, thigh. Caliper technique strongly affects results; take each site 2–3 times and average. Research equation, not a measurement.
Frequently asked questions
Men: chest, abdomen and thigh. Women: triceps, suprailiac (just above the hip bone) and thigh. This tool's site inputs are labelled for both.
The sum of the three skinfolds (with age) enters the Jackson–Pollock equation to estimate body density; the Siri equation then converts density to body fat %: 495 ÷ density − 450.
Pinch the skin and underlying fat away from muscle, place the caliper 1 cm below your fingers, read after 2 seconds, and repeat 2–3 times per site, averaging. Measure on the same side of the body each time.
With practised technique, roughly ±3–4 percentage points versus reference methods; beginners and very lean or very high body-fat levels err more. Consistency matters more than the absolute number for tracking.
Yes — Jackson–Pollock also published 7-site equations (adding triceps, subscapular, midaxillary and suprailiac/chest sites). The 3-site version here is the most commonly used field method.