Home›Calculators›Health›Skinfold Body Fat Calculator

Skinfold Body Fat Calculator

Health

Estimate body fat percentage from 3-site skinfold measurements using the Jackson-Pollock formula and Siri equation, with sex-specific calculations.

Sex
Age
years
Chest Skinfold
mm
Abdomen Skinfold
mm
Thigh Skinfold
mm

Use skinfold calipers to pinch and measure each site to the nearest 0.5 mm. Sites differ by sex per the Jackson-Pollock 3-site protocol.

Body Fat Percentage

—

Estimate only. Jackson-Pollock 3-site skinfold results depend on measurement technique and caliper accuracy — for clinical accuracy, use DEXA or hydrostatic weighing.

What is a Skinfold Body Fat?

A Skinfold Body Fat Calculator estimates your body fat percentage using the Jackson-Pollock 3-site method, a field technique that measures skin and subcutaneous fat thickness at three specific body locations with a handheld caliper. Unlike the Body Fat Calculator, which typically uses circumference-based formulas, this method relies on direct physical measurements of fat thickness, making it one of the more established approaches used by trainers, coaches, and sports scientists outside of clinical lab settings.

The method works by converting your three skinfold measurements — combined with age and sex — into an estimate of body density using a validated regression equation. That density figure is then converted into a familiar body fat percentage using the Siri equation. Because fat distribution differs between men and women, the calculator uses different measurement sites and formulas for each: chest, abdomen, and thigh for men; triceps, suprailiac, and thigh for women.

Skinfold testing sits between simple estimation tools and expensive lab methods like DEXA scanning in terms of both cost and accuracy. It requires a caliper and some practice, but in experienced hands it delivers meaningfully more individualized results than formulas based on height and weight alone, such as the BMI Calculator.

How to use this Skinfold Body Fat calculator

  1. Select your Sex — the calculator uses different measurement sites and formulas for men and women.
  2. Enter your Age in years.
  3. Using a skinfold caliper, measure Site 1 (Chest for men, Triceps for women) in millimeters and enter the value.
  4. Measure Site 2 (Abdomen for men, Suprailiac for women) and enter the value.
  5. Measure Site 3 (Thigh, for both sexes) and enter the value.
  6. Review your Body Fat Percentage result and category badge, along with the calculated Body Density figure, to understand where you fall relative to typical fitness benchmarks.

Formula & Methodology

The calculator sums your three skinfold measurements (Sum3, in mm) and applies the sex-specific Jackson-Pollock 3-site regression equation to estimate body density:

Men: Body Density = 1.10938 − (0.0008267 × Sum3) + (0.0000016 × Sum3²) − (0.0002574 × Age)

Women: Body Density = 1.0994921 − (0.0009929 × Sum3) + (0.0000023 × Sum3²) − (0.0001392 × Age)

Body density is then converted to body fat percentage using the Siri equation:

Body Fat % = (495 ÷ Body Density) − 450

Worked example: For a 30-year-old man with skinfold measurements of 12 mm (chest), 15 mm (abdomen), and 14 mm (thigh):
- Sum3 = 12 + 15 + 14 = 41 mm
- Body Density = 1.10938 − (0.0008267 × 41) + (0.0000016 × 41²) − (0.0002574 × 30)
- Body Density ≈ 1.10938 − 0.03389 + 0.00269 − 0.00772 ≈ 1.0705
- Body Fat % = (495 ÷ 1.0705) − 450 ≈ 462.4 − 450 ≈ 12.4%

This places the individual in the Fit to Athletic range on standard body fat category charts.

Frequently Asked Questions

It's a body composition estimation technique that uses a caliper to measure skin thickness at three specific body sites, then plugs those measurements into a validated regression formula to estimate body density and, from that, body fat percentage. It was developed by Jackson and Pollock in the 1980s and remains one of the most widely used field methods for estimating body fat outside a lab.
For men, the standard 3-site protocol measures the chest, abdomen, and thigh. For women, the protocol instead measures the triceps, suprailiac (just above the hip bone), and thigh, since fat distribution patterns differ by sex.
In the hands of an experienced, consistent tester, skinfold testing typically estimates body fat within about 3–4% of more precise lab methods like DEXA scanning. Accuracy drops significantly with inconsistent caliper technique, so using the same tester and measurement sites each time produces more reliable trend data than absolute precision.
Body density is an intermediate physical measurement, in grams per cubic centimeter, that reflects the ratio of fat to lean tissue in the body — fat tissue is less dense than muscle and bone. The Siri equation then converts this density figure into the body fat percentage most people are familiar with, using the formula (495 ÷ Body Density) − 450.
Skinfold testing requires a caliper and hands-on technique but tends to produce more individualized estimates since it directly measures subcutaneous fat at multiple sites. The [RFM Calculator](/rfm-calculator/) only needs a tape measure and height, making it far more accessible, though it relies on a simpler waist-to-height formula rather than direct fat measurement.
Select your sex, enter your age, then measure and enter the three skinfold thicknesses in millimeters using a body fat caliper at the sites indicated for your sex. The calculator instantly returns your estimated body density and body fat percentage.
You need a skinfold caliper, a handheld tool that pinches a fold of skin and subcutaneous fat and reads the thickness in millimeters. Basic plastic calipers are inexpensive and adequate for personal tracking, while spring-loaded metal calipers offer more consistent pressure for repeated measurements.
Yes, but self-measurement is less accurate than having a trained partner take the readings, particularly for sites like the back of the thigh that are hard to reach and pinch consistently. If precise tracking matters to you, consider having the same person measure you each time to reduce technique-related variability.
The calculator displays your estimated body fat percentage alongside standard category bands — Essential Fat, Athletic, Fit, Acceptable, and Obese — which differ for men and women due to natural differences in essential fat levels. These bands provide context for whether your result falls within a typical, athletic, or higher-risk range.
No — skinfold measurements, even when taken carefully, are an estimate that depends heavily on tester technique and calipers used. For clinical-grade accuracy, methods like DEXA scanning, hydrostatic weighing, or Bod Pod air displacement plethysmography are more reliable, and this tool should not replace guidance from a healthcare provider.
The Jackson-Pollock equations include an age term because body fat distribution and skin compressibility change with age, affecting the relationship between skinfold thickness and total body fat. Including age improves the formula's accuracy compared to using skinfold thickness alone.
Every 3–4 weeks is generally a reasonable interval, since body composition changes gradually and more frequent testing mainly captures measurement noise rather than real change. Taking measurements at a consistent time of day, using the same sites and technique, will make comparisons across sessions more meaningful.
Also known as
skinfold calculatorJackson Pollock body fat3-site skinfold testcaliper body fat calculatorbody density calculatorSiri equation calculator