Jackson-Pollock Body Fat Calculator (3-Site Skinfold Method)
Calculate body fat percentage with the Jackson-Pollock 3-site skinfold method. Enter your caliper readings to get body density, fat mass, lean mass, and ACE classification instantly.
See step-by-step calculation
When to use this calculator
- Tracking body composition changes during a cut or bulk
- Baseline fitness assessment before starting a new training program
- Comparing body fat levels against ACE health classification standards
- Estimating lean body mass to calculate daily protein targets
- Monitoring fat loss progress more accurately than scale weight alone
- Pre-competition body composition check for natural athletes
ACE Body Fat % Classification — Men vs. Women
| Category | Men (%) | Women (%) |
|---|---|---|
| Essential fat | 2–5 | 10–13 |
| Athletes | 6–13 | 14–20 |
| Fitness | 14–17 | 21–24 |
| Average | 18–24 | 25–31 |
| Obese | ≥ 25 | ≥ 32 |
Fuente: American Council on Exercise — ACE Fitness (2024)
How it works
How the Jackson-Pollock 3-Site Method Works
The Jackson-Pollock method estimates body fat % by measuring the thickness of subcutaneous fat at three standardized anatomical sites with a skinfold caliper. The sum of those three measurements, combined with age, is fed into a sex-specific regression equation to compute body density (Db). Body density is then converted to a body fat percentage using the Siri two-compartment equation.
The Formulas
// Step 1 — sum the three skinfolds
S = skinfold1 + skinfold2 + skinfold3 (mm)
// Step 2 — calculate body density
// Men (chest + abdominal + thigh) — Jackson & Pollock, 1978
Db = 1.10938 − (0.0008267 × S) + (0.0000016 × S²) − (0.0002574 × Age)
// Women (triceps + suprailiac + thigh) — Jackson, Pollock & Ward, 1980
Db = 1.0994921 − (0.0009929 × S) + (0.0000023 × S²) − (0.0001392 × Age)
// Step 3 — Siri equation (body fat %)
Body Fat % = ((4.95 / Db) − 4.50) × 100
// Step 4 — mass partitioning
Fat Mass = Total Weight × (Body Fat % / 100)
Lean Mass = Total Weight − Fat MassWorked Example — Male, 35 years, 175 lb
| Input | Value |
|---|---|
| Sex | Male |
| Age | 35 years |
| Chest skinfold | 15 mm |
| Abdominal skinfold | 20 mm |
| Thigh skinfold | 18 mm |
| Sum (S) | 53 mm |
| Body density (Db) | 1.0647 g/mL |
| Body Fat % | 17.2% |
| Fat Mass | 30.1 lb |
| Lean Mass | 144.9 lb |
| ACE Classification | Fitness |
ACE Body Fat Classification Reference Table
| Category | Men (%) | Women (%) |
|---|---|---|
| Essential fat | 2–5 | 10–13 |
| Athletes | 6–13 | 14–20 |
| Fitness | 14–17 | 21–24 |
| Average | 18–24 | 25–31 |
| Obese | ≥ 25 | ≥ 32 |
Body Fat % by Sum of Skinfolds — Quick Reference (Men, Age 30)
This table shows how body fat % changes with skinfold sum for a typical 30-year-old male:
| Sum of 3 skinfolds (mm) | Body Density (g/mL) | Body Fat % | ACE Category |
|---|---|---|---|
| 30 mm | 1.0871 | 10.7% | Athlete |
| 45 mm | 1.0724 | 14.2% | Fitness |
| 60 mm | 1.0560 | 18.5% | Average |
| 75 mm | 1.0380 | 23.5% | Average |
| 90 mm | 1.0183 | 28.8% | Obese |
| 105 mm | 0.9969 | 34.7% | Obese |
Measurement Technique
1. Locate the site: Use anatomical landmarks (for chest: diagonal fold midway between anterior axillary line and nipple; for abdomen: vertical fold 2 cm lateral to navel; for thigh: vertical fold midway between kneecap and inguinal fold).
2. Pinch correctly: Grasp a fold of skin and underlying subcutaneous fat only — not muscle — between thumb and index finger.
3. Apply caliper: Place caliper jaws 1 cm from your fingers, perpendicular to the fold.
4. Read at 2 seconds: Release the caliper lever and read the dial after 2 seconds (before the fold compresses further).
5. Triple measure and average: Take three readings per site and average them for reliability.
Limitations to Know
Frequently asked questions
What sites do I measure for men vs. women?
How accurate is the Jackson-Pollock 3-site method?
How do I measure a skinfold correctly?
What is the Siri equation and why is it used?
What is a good body fat percentage for men?
What is a healthy body fat percentage for women?
Can I use this calculator if I'm over 60?
What does lean mass include — is it the same as muscle?
Why does my result differ from a bioimpedance (BIA) scale?
Is lower body fat always better?
How does this compare to the 7-site Jackson-Pollock method?
Sources & references
- Jackson AS, Pollock ML. Generalized equations for predicting body density of men. Br J Nutr. 1978;40(3):497–504. — PubMed / NCBI (1978)
- Jackson AS, Pollock ML, Ward A. Generalized equations for predicting body density of women. Med Sci Sports Exerc. 1980;12(3):175–181. — PubMed / NCBI (1980)
- Siri WE. Body composition from fluid spaces and density: analysis of methods. Techniques for Measuring Body Composition. 1956. — PubMed / NCBI (1956)
- American Council on Exercise (ACE) — Percent Body Fat Norms for Men and Women — ACE Fitness (2024)
- ACSM — American College of Sports Medicine Body Composition Guidelines — ACSM (2024)
- NIH Body Weight Planner & Body Composition Background — National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (2025)
Methodology & trust
Calculadora de salud revisada por el equipo editorial de Hacé Cuentas, contrastada con Jackson AS, Pollock ML. Generalized equations for predicting body density of men. Br J Nutr. 1978;40(3):497–504., según nuestra política editorial y metodología.
Última revisión: June 20, 2026. Los parámetros se verifican periódicamente con las fuentes citadas.
Calculations run 100% in your browser. We do not store or transmit your data.
Indicative results. For critical decisions, consult a professional.
Rodríguez, M. (2026). Jackson-Pollock Body Fat Calculator (3-Site Skinfold Method). Hacé Cuentas. https://hacecuentas.com/body-fat-jackson-pollock-calculator
Contenido bajo licencia CC-BY 4.0 — reutilizable citando la fuente con enlace a Hacé Cuentas.