📐 4-Site Skinfold Calculator
Calculate your body fat percentage using the classic Durnin & Womersley (1974) 4-site skinfold method
4-Site Skinfold Calculator: Complete Durnin & Womersley Guide
The Durnin & Womersley (1974) 4-site skinfold method is the classic gold standard for body fat assessment using calipers. This scientifically validated protocol provides accurate body composition analysis using four measurement sites: biceps, triceps, subscapular, and suprailiac. Measurements can be taken in millimeters (mm) or inches with automatic conversion for precise calculations.
📏 Classic 4-Site Protocol
The Durnin & Womersley method uses four specific skinfold sites for both men and women. Research demonstrates this approach with high correlation coefficients compared to hydrostatic weighing across diverse populations. For comprehensive fitness guidance, explore our body fat percentage chart and visual body fat assessment guide.
🔬 Age-Specific Equations
Uses age-specific logarithmic equations for different age groups (16-19, 20-29, 30-39, 40-49, 50+ years). Studies validate the age-specific approach for improved accuracy across the lifespan.
⚖️ Universal Sites
All Participants: Biceps, Triceps, Subscapular, Suprailiac
Unlike other methods, Durnin & Womersley uses the same four sites for both genders, making it simpler to administer.
📊 Body Fat Standards by Age and Gender
| Category | Men (18-29) | Men (30-49) | Men (50+) | Women (18-29) | Women (30-49) | Women (50+) |
|---|---|---|---|---|---|---|
| Essential Fat | 2-5% | 2-5% | 2-5% | 10-13% | 10-13% | 10-13% |
| Athletes | 6-13% | 7-16% | 9-18% | 14-20% | 16-23% | 18-27% |
| Fitness | 14-17% | 17-19% | 19-21% | 21-24% | 24-27% | 27-30% |
| Average | 18-24% | 21-27% | 24-29% | 25-31% | 28-34% | 31-37% |
| Above Average | 25%+ | 28%+ | 30%+ | 32%+ | 35%+ | 38%+ |
📐 4-Site Measurement Instructions
💪 Biceps Skinfold
Location: Vertical fold on the front of the upper arm
Technique: Measure over the belly of the biceps muscle, midway between the acromion and olecranon processes
Direction: Fold runs parallel to the long axis of the arm
🔧 Triceps Skinfold
Location: Vertical fold on the back of the upper arm
Technique: Measure over the triceps muscle, midway between acromion and olecranon
Direction: Fold runs parallel to the long axis of the arm
🎯 Subscapular Skinfold
Location: Diagonal fold below the inferior angle of the scapula
Technique: Fold follows the natural line of the skin, approximately 45° to horizontal
Direction: Diagonal fold running medially downward
⚡ Suprailiac Skinfold
Location: Diagonal fold above the iliac crest
Technique: Measure at the anterior axillary line, above the iliac crest
Direction: Fold follows the natural line of the skin
🧮 Durnin & Womersley Formula & Protocol
Step 1: Take Measurements
• Use calibrated skinfold calipers (Lange, Harpenden, or similar)
• Take 3 measurements at each site, use median value
• Apply 10g/mm² pressure consistently
• Read measurement 2 seconds after full pressure applied
Step 2: Calculate Body Density (Age-Specific Equations)
Men (Durnin & Womersley, 1974):
16-19 years: BD = 1.1620 - (0.0630 × log₁₀(Sum))
20-29 years: BD = 1.1631 - (0.0632 × log₁₀(Sum))
30-39 years: BD = 1.1422 - (0.0544 × log₁₀(Sum))
40-49 years: BD = 1.1620 - (0.0700 × log₁₀(Sum))
50+ years: BD = 1.1715 - (0.0779 × log₁₀(Sum))
Women (Durnin & Womersley, 1974):
16-19 years: BD = 1.1549 - (0.0678 × log₁₀(Sum))
20-29 years: BD = 1.1599 - (0.0717 × log₁₀(Sum))
30-39 years: BD = 1.1423 - (0.0632 × log₁₀(Sum))
40-49 years: BD = 1.1333 - (0.0612 × log₁₀(Sum))
50+ years: BD = 1.1339 - (0.0645 × log₁₀(Sum))
Step 3: Convert to Body Fat %
Body Fat % = ((4.95 ÷ Body Density) - 4.50) × 100
Using the Siri equation (1961)
Example: 25-year-old male, measurements: Biceps 6mm, Triceps 10mm, Subscapular 12mm, Suprailiac 8mm
Sum = 36mm, log₁₀(36) = 1.556, BD = 1.0647, Body Fat = 15.9%
Result: Fitness category for age group
💡 Measurement Tips & Best Practices
Proper Technique
Pinch skin and fat away from muscle. Maintain 10g/mm² pressure. Take measurements on right side of body. Ensure consistent technique across all four sites.
Timing Considerations
Measure at same time of day. Avoid post-exercise or post-meal measurements. Ensure proper hydration status for consistency.
Reliability
Take 3 measurements per site, use median value. Repeat measurements if values differ by >2mm. Train for consistency across sessions.
Equipment Quality
Use calibrated calipers (±0.5mm accuracy). Popular brands: Lange, Harpenden, Accu-Measure. Regular calibration ensures measurement accuracy.
⚖️ Method Comparison & Historical Significance
The Durnin & Womersley (1974) method is considered the foundational work in skinfold body composition assessment. Historical analysis shows its lasting impact:
| Method | Year | Sites | Age Groups | Sample Size | Correlation (r) |
|---|---|---|---|---|---|
| Durnin & Womersley | 1974 | 4 sites | 5 groups | 481 subjects | 0.92-0.97 |
| Jackson & Pollock (Men) | 1978 | 3 sites | Continuous | 403 subjects | 0.91 |
| Jackson, Pollock & Ward (Women) | 1980 | 3 sites | Continuous | 249 subjects | 0.84 |
| Slaughter et al. | 1988 | 2 sites | Youth only | 310 subjects | 0.89 |
Historical Significance:
- First comprehensive age-specific skinfold equations
- Established the 4-site measurement protocol
- Validated across wide age range (16-72 years)
- Used logarithmic transformation for improved accuracy
- Foundation for subsequent skinfold research
- Still widely used in clinical and research settings
🏥 Clinical Applications & Research Uses
Clinical Assessment
Applications: Obesity evaluation, weight loss monitoring, metabolic health assessment
Advantages: Non-invasive, cost-effective, no radiation exposure, suitable for repeated measurements
Research Applications
Uses: Population studies, intervention trials, epidemiological research, athletic performance studies
Benefits: Standardized protocol, age-specific equations, extensive validation literature
Population Studies
Scope: Large-scale health surveys, cross-cultural studies, longitudinal aging research
Value: Validated across diverse populations and ethnic groups
Limitations & Considerations
Factors: Requires trained technician, affected by hydration, assumes constant tissue density
Accuracy: ±3-4% standard error when performed correctly by experienced practitioners
References
- Davidson LE, Wang J, Thornton JC, Kaleem Z, Silva-Palacios F, Pierson RN, Heymsfield SB, Gallagher D. Predicting fat percent by skinfolds in racial groups: Durnin and Womersley revisited. Med Sci Sports Exerc. 2011 Mar;43(3):542-9. doi: 10.1249/MSS.0b013e3181ef3f07. PMID: 20689462; PMCID: PMC3308342.
- Peterson, M. J., Czerwinski, S. A., & Siervogel, R. M. (2003). Development and validation of skinfold-thickness prediction equations with a 4-compartment model. The American Journal of Clinical Nutrition, 77(5), 1186-1191. https://doi.org/10.1093/ajcn/77.5.1186
- Chambers AJ, Parise E, McCrory JL, Cham R. A comparison of prediction equations for the estimation of body fat percentage in non-obese and obese older Caucasian adults in the United States. J Nutr Health Aging. 2014;18(6):586-90. doi: 10.1007/s12603-014-0017-3. PMID: 24950148; PMCID: PMC4396823.
Manish is a NASM-certified fitness and nutrition coach with over 10 years of experience in weight lifting and fat loss fitness coaching. He specializes in gym-based training and has a lot of knowledge about exercise, lifting technique, biomechanics, and more.
Through “Fit Life Regime,” he generously shares the insights he’s gained over a decade in the field. His goal is to equip others with the knowledge to start their own fitness journey.