Skinfold Body Fat Calculator
Calculate body-fat percentage with the Jackson-Pollock 3-site skinfold method, using age and caliper measurements for men and women.
By Jonas Lindemann · Updated · How we build our calculators
Measure each site with calipers. Men use chest, abdomen, and thigh; women use triceps, suprailiac, and thigh.
13.6%
Athletes
45.0 mm
sum of 3 sites
Athletes
category
Note: The Jackson-Pollock 3-site method is accurate to roughly 3-4% with good caliper technique. Take each measurement on the right side and average two readings. Informational only.
Get Weekly Training Tips
Join our newsletter for expert insights, training advice, and performance tips delivered to your inbox.
No spam, unsubscribe anytime. We respect your privacy.
Calculation Method
The Jackson-Pollock 3-site skinfold method estimates body-fat percentage from caliper measurements at three sites. By measuring the fat layer just under the skin, it predicts overall body density and converts that to a body-fat figure — a fast, low-cost technique that is accurate to within about 3-4% when done with good technique.
The Formula
Sex-specific equations predict body density from the sum of three skinfolds (mm) and age, then the Siri equation converts density to body-fat percentage. Men measure chest, abdomen, and thigh; women measure triceps, suprailiac, and thigh.
Women: D = 1.0994921 − 0.0009929×S + 0.0000023×S2 − 0.0001392×age
Body fat % = (495 / D) − 450 (Siri)
S is the sum of the three skinfolds in millimetres.
Worked Example
A 30-year-old man with chest 12 mm, abdomen 18 mm, thigh 15 mm (sum = 45 mm):
- D = 1.10938 − 0.0008267×45 + 0.0000016×452 − 0.0002574×30
- D ≈ 1.10938 − 0.0372 + 0.0032 − 0.0077 = 1.0676
- Body fat = 495 / 1.0676 − 450 ≈ 13.7% → Athletes range
Body-Fat Categories
| Category | Men | Women |
|---|---|---|
| Essential fat | 2 – 5% | 10 – 13% |
| Athletes | 6 – 13% | 14 – 20% |
| Fitness | 14 – 17% | 21 – 24% |
| Average | 18 – 24% | 25 – 31% |
| Above average | ≥ 25% | ≥ 32% |
Measuring Well
- Pinch the skinfold firmly, place the caliper 1 cm from your fingers, and read after 1-2 seconds.
- Take all readings on the right side of the body.
- Measure each site twice and average; if readings differ by more than 1-2 mm, take a third.
Note: Skinfold estimates depend heavily on caliper technique and site location. This is an informational body-composition tool, not a clinical measurement. For medical assessment, consult a qualified professional.
Frequently Asked Questions
Men measure the chest, abdomen, and thigh; women measure the triceps, suprailiac, and thigh. The sum of the three folds feeds the body-density equation.
With good caliper technique it is accurate to within about 3-4% of lab methods. Consistent site location and pinch technique matter more than the brand of caliper.
Pinch the fold firmly, place the caliper about 1 cm from your fingers, and read after 1-2 seconds. Measure on the right side of the body and average two readings per site.
For men, 14-17% is fitness level and 6-13% is athletic; for women, 21-24% is fitness and 14-20% is athletic. Essential fat is 2-5% for men and 10-13% for women.