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Body Fat % Calculator by Skinfolds

Q: What type of caliper should I use?

Research-validated protocols use **Harpenden** or **Lange** calipers, which apply a standardized jaw pressure of **10 g/mm²** across the full measurement range. Consumer-grade plastic calipers (e.g., Accu-Measure) are less consistent and typically have test-retest errors of ±3–5%, compared to ±1% for professional calipers. For gym or home use, plastic calipers are acceptable for rough tracking, but clinical or research assessments require calibrated metal calipers.

Q: Where exactly are the measurement sites located?

**Men — Chest:** diagonal fold halfway between the anterior axillary line and the nipple. **Men — Abdomen:** vertical fold 2 cm to the right of the navel. **Both sexes — Thigh:** vertical fold on the anterior midline of the thigh, halfway between the inguinal crease and the proximal border of the patella. **Women — Triceps:** vertical fold on the posterior midline of the upper arm, halfway between the acromion and olecranon. **Women — Suprailiac:** diagonal fold just above the iliac crest at the anterior axillary line.

Q: Can I use this calculator if I am over 60 or under 18?

The Jackson-Pollock equations were validated on adults **aged 18–61**. Applying them outside this range increases prediction error because body fat distribution and density of lean tissue change significantly with aging (lean mass density decreases after ~60) and in adolescents (whose bodies are still developing). For older adults, the **Durnin-Womersley 4-site method** or **DEXA** is generally preferred. For children and teens, CDC growth charts and pediatric-specific skinfold equations (e.g., Slaughter et al., 1988) are recommended.

Q: Why does the formula use body density instead of skinfolds directly?

Subcutaneous fat (measured by calipers) is only a **proxy** for total body fat. The Jackson-Pollock regression converts skinfold thicknesses into estimated whole-body **density** (g/mL), exploiting the physiological principle that fat tissue (~0.9 g/mL) is less dense than lean tissue (~1.1 g/mL). The Siri equation (1956) then converts density to % fat via the two-compartment model: **(495 ÷ BD) − 450**. This two-step approach is more biologically grounded than a direct skinfold-to-fat regression.

Q: What is the best time of day and conditions for taking skinfold measurements?

Measurements should be taken in the **morning**, at least **2 hours after eating**, and **not after exercise** or a hot shower (heat and exertion increase blood flow and can transiently thicken skin folds). Hydration status matters: dehydration of just **1–2% body weight** can reduce skinfold readings by 5–10%. Always measure under the same conditions each time. The same technician should perform repeated assessments because inter-tester variability (~3–5%) exceeds intra-tester variability (~1–2%).

Q: How does body fat % from skinfolds compare to BMI for health risk assessment?

BMI classifies weight relative to height but **cannot distinguish fat from muscle**. A muscular 90 kg athlete may have a BMI of 27 (overweight) but only 12% body fat. Conversely, a 'normal-weight' sedentary person (BMI 22) could carry 27% body fat — a condition called **normal-weight obesity** or 'skinny fat,' associated with metabolic syndrome. The NIH and ACSM recognize that body fat percentage is a more direct health-risk indicator than BMI, particularly for athletes and older adults with reduced muscle mass.

Q: What body fat percentages are considered healthy by major health organizations?

The **American Council on Exercise (ACE)** defines healthy ranges as **18–24% for men** and **25–31% for women**. The **WHO** and **NIH** use similar thresholds, with obesity defined at ≥25% (men) and ≥32% (women). Essential fat — the minimum needed for physiological function — is **2–5% (men)** and **10–13% (women)**. Competitive athletes typically fall in the **6–13% (men)** and **14–20% (women)** ranges. Going below essential fat levels risks hormonal disruption, bone loss, and immune suppression.

Body fat calculator: estimate your body fat percentage using the Jackson-Pollock 3-site skinfold formula. Measure with calipers and get your category.

🗓️ Updated June 2026 Reviewed by Martín Rodríguez

Calculator Free · Private

Reviewed by: Martín Rodríguez (editorial policy ) · Last reviewed: Jun 20, 2026

Sex

Age*

Weight (kg)

Skinfold 1 (mm) — Men: chest / Women: triceps*

Skinfold 2 (mm) — Men: abdomen / Women: suprailiac*

Skinfold 3 (mm) — Thigh (both)*

🧮 Keep calculating

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.Body Composition Calculator: Fat Mass vs Lean MassCalculate your fat mass and lean mass in kg from your body weight and body fat percentage. Bicompartmental formula + ACSM reference ranges by sex. Instant result.Body Fat Percentage Calculator (US Navy Method)Calculate your body fat percentage using the US Navy method with just a tape measure. No scale, no equipment. Classified by ACE standards.Subcutaneous vs Visceral Fat: Understanding the DifferenceCalculate how much of your total body fat is visceral (organ-surrounding) versus subcutaneous (under-skin). Enter your total body fat % and visceral fat share to see the split and your metabolic risk level.

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The Jackson-Pollock 3-Site Skinfold method estimates body fat percentage by measuring subcutaneous fat at three specific body sites with calipers, calculating body density, and converting it to % fat using the Siri equation. For men, the three sites are chest, abdomen, and thigh; for women, triceps, suprailiac, and thigh. It is widely used by fitness professionals, athletic trainers, and researchers because it is fast, low-cost, reproducible, and more accurate than BMI for assessing body composition. The method is valid for adults aged 18–61 and assumes a two-compartment model (fat mass vs. lean mass).

When to use this calculator

An athlete tracking seasonal changes in body composition to optimize their strength-to-weight ratio before competition.
A personal trainer performing a client intake assessment to set realistic fat-loss goals and calculate lean mass targets.
A college sports science student learning and applying the Jackson-Pollock protocol in a lab exercise on body composition measurement.
A recreational gym-goer monitoring progress over a 12-week cut or bulk phase when scale weight alone is misleading.
A military fitness instructor evaluating whether a service member meets body composition standards as a complement to tape-measure tests.
A physical therapist designing a rehabilitation program who needs baseline body composition data beyond BMI for an overweight patient.

Jackson-Pollock 3-Site Skinfold Measurement Locations (Protocol)

Site	Sex	Fold Orientation	Anatomical Landmark	Common Error
Chest	Men only	Diagonal	Halfway between anterior axillary line and nipple	Measuring too close to nipple; not diagonal
Abdomen	Men only	Vertical	2 cm to the right of the navel (umbilicus)	Including muscle; not fully vertical pinch
Triceps	Women only	Vertical	Posterior midline of upper arm, halfway between acromion and olecranon	Arm not relaxed and hanging straight down
Suprailiac	Women only	Diagonal	Just above iliac crest at the anterior axillary line	Measuring too far posterior or inferior
Thigh	Both sexes	Vertical	Anterior midline of thigh, halfway between inguinal crease and proximal border of patella	Measuring on the wrong leg; should be right side only

Source: Jackson & Pollock (1978), Medicine & Science in Sports 10(3):175–181; CDC NHANES Body Composition Procedures Manual. All sites measured on the RIGHT side of the body only. Caliper jaw pressure: 10 g/mm² (Harpenden or Lange standard).

How it works

How It's Calculated

The Jackson-Pollock 3-Site method uses two sequential formulas: one to estimate body density from skinfold measurements and age, and a second to convert density to % body fat.

Step 1 — Body Density (BD)

Men (chest + abdomen + thigh):

S = skinfold_chest + skinfold_abdomen + skinfold_thigh   (sum in mm)

BD = 1.10938 - (0.0008267 × S) + (0.0000016 × S²) - (0.0002574 × Age)

Women (triceps + suprailiac + thigh):

S = skinfold_triceps + skinfold_suprailiac + skinfold_thigh   (sum in mm)

BD = 1.0994921 - (0.0009929 × S) + (0.0000023 × S²) - (0.0001392 × Age)

Step 2 — % Body Fat via Siri Equation (1956)

% Body Fat = (495 ÷ BD) - 450

Step 3 — Fat Mass & Lean Mass

Fat Mass (kg)  = Body Weight (kg) × (% Body Fat ÷ 100)
Lean Mass (kg) = Body Weight (kg) − Fat Mass (kg)

> Measurement tip: All skinfolds are taken on the right side of the body, using a Lange or Harpenden caliper. The pinch is held for 2 seconds before reading. Take 3 readings per site and average them if they differ by more than 1 mm.

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Reference Table

Men — Body Fat % Categories (American Council on Exercise)

Category	Body Fat % (Men)	Body Fat % (Women)
Essential fat	2 – 5 %	10 – 13 %
Athletes	6 – 13 %	14 – 20 %
Fitness	14 – 17 %	21 – 24 %
Acceptable	18 – 24 %	25 – 31 %
Obese	≥ 25 %	≥ 32 %

Typical Skinfold Sums by Fitness Level (Men, Age 25–35)

Fitness Level	Typical Sum (mm)	Approx. BD	Approx. % Fat
Lean athlete	20 – 35 mm	1.072 – 1.082	6 – 11 %
Fitness	36 – 54 mm	1.058 – 1.072	12 – 17 %
Acceptable	55 – 85 mm	1.038 – 1.058	18 – 24 %
Overfat	> 85 mm	< 1.038	> 25 %

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Typical Examples

Example 1 — Male, Age 28, 80 kg (Fitness category)

Sites: chest = 10 mm, abdomen = 15 mm, thigh = 12 mm

S = 37 mm

BD = 1.10938 − (0.0008267 × 37) + (0.0000016 × 1369) − (0.0002574 × 28)

BD = 1.10938 − 0.030588 + 0.0021904 − 0.0072072 = 1.0625

% Fat = (495 ÷ 1.0625) − 450 = 15.9% → Fitness ✅

Fat Mass = 80 × 0.159 = 12.7 kg | Lean Mass = 67.3 kg

Example 2 — Female, Age 35, 65 kg (Acceptable category)

Sites: triceps = 18 mm, suprailiac = 22 mm, thigh = 28 mm

S = 68 mm

BD = 1.0994921 − (0.0009929 × 68) + (0.0000023 × 4624) − (0.0001392 × 35)

BD = 1.0994921 − 0.067517 + 0.010635 − 0.004872 = 1.0377

% Fat = (495 ÷ 1.0377) − 450 = 27.1% → Acceptable

Fat Mass = 65 × 0.271 = 17.6 kg | Lean Mass = 47.4 kg

Example 3 — Male, Age 45, 90 kg (Overfat)

Sites: chest = 20 mm, abdomen = 32 mm, thigh = 25 mm

S = 77 mm

BD = 1.10938 − (0.0008267 × 77) + (0.0000016 × 5929) − (0.0002574 × 45)

BD = 1.10938 − 0.063656 + 0.009486 − 0.011583 = 1.0443

% Fat = (495 ÷ 1.0443) − 450 = 24.0% → Upper Acceptable / borderline Overfat

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Common Errors

1. Measuring on the wrong side of the body. The Jackson-Pollock protocol specifies the right side only. Switching sides or averaging both introduces systematic error of up to 2–3 mm per site.

2. Not waiting 2 seconds before reading the caliper. Fat tissue compresses over time. Reading immediately overestimates thickness; waiting the full 2 seconds ensures a standardized, reproducible pinch.

3. Pinching muscle along with fat. The skinfold must capture only the subcutaneous fat layer — not underlying muscle. This is especially common at the abdominal site in individuals with low hydration or high muscle tone, and can inflate the skinfold by 3–5 mm.

4. Using the formula for the wrong sex. The regression coefficients differ significantly between men and women. Applying the male formula to a female subject (or vice versa) can produce errors of 4–8 percentage points.

5. Ignoring hydration and skin temperature. Dehydration can thin skinfold readings by 5–10%; measuring immediately after exercise or a hot shower causes vasodilation and can transiently thicken readings. Always measure under standardized, rested conditions.

6. Using cheap or uncalibrated calipers. Research-grade Harpenden or Lange calipers exert a constant pressure of 10 g/mm². Plastic calipers may exert variable pressure, reducing test-retest reliability from ±1% to ±3–5%.

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Related Calculators

BMI Calculator

Ideal Weight Calculator

Basal Metabolic Rate (BMR) Calculator

Waist-to-Hip Ratio Calculator

Example: 28-year-old man, skinfolds 10/15/12 mm

Sum of skinfolds: 10+15+12 = 37 mm.

Density: 1.10938 - 0.0008267×37 + 0.0000016×37² - 0.0002574×28 = 1.0625.

% Fat (Siri): (495/1.0625) - 450 = 15.9%.

Category: Fitness (14–18% men).

Body fat percentage: 15.9% — Category: Fitness.

Frequently asked questions

How accurate is the Jackson-Pollock 3-Site method compared to DEXA?

When performed by a trained technician, the Jackson-Pollock 3-Site method has a standard error of estimate (SEE) of approximately ±3–4% body fat versus DEXA (considered a gold standard). Jackson & Pollock's original 1978 study (Medicine & Science in Sports) reported an SEE of 3.4% for men and 3.9% for women. DEXA itself carries an SEE of ~1–2%, but costs $50–$200 per scan. For tracking relative changes over time (rather than absolute values), skinfolds are a practical and widely validated alternative.

What type of caliper should I use?

Research-validated protocols use Harpenden or Lange calipers, which apply a standardized jaw pressure of 10 g/mm² across the full measurement range. Consumer-grade plastic calipers (e.g., Accu-Measure) are less consistent and typically have test-retest errors of ±3–5%, compared to ±1% for professional calipers. For gym or home use, plastic calipers are acceptable for rough tracking, but clinical or research assessments require calibrated metal calipers.

Where exactly are the measurement sites located?

Men — Chest: diagonal fold halfway between the anterior axillary line and the nipple. Men — Abdomen: vertical fold 2 cm to the right of the navel. Both sexes — Thigh: vertical fold on the anterior midline of the thigh, halfway between the inguinal crease and the proximal border of the patella. Women — Triceps: vertical fold on the posterior midline of the upper arm, halfway between the acromion and olecranon. Women — Suprailiac: diagonal fold just above the iliac crest at the anterior axillary line.

Can I use this calculator if I am over 60 or under 18?

The Jackson-Pollock equations were validated on adults aged 18–61. Applying them outside this range increases prediction error because body fat distribution and density of lean tissue change significantly with aging (lean mass density decreases after ~60) and in adolescents (whose bodies are still developing). For older adults, the Durnin-Womersley 4-site method or DEXA is generally preferred. For children and teens, CDC growth charts and pediatric-specific skinfold equations (e.g., Slaughter et al., 1988) are recommended.

Why does the formula use body density instead of skinfolds directly?

Subcutaneous fat (measured by calipers) is only a proxy for total body fat. The Jackson-Pollock regression converts skinfold thicknesses into estimated whole-body density (g/mL), exploiting the physiological principle that fat tissue (~0.9 g/mL) is less dense than lean tissue (~1.1 g/mL). The Siri equation (1956) then converts density to % fat via the two-compartment model: (495 ÷ BD) − 450. This two-step approach is more biologically grounded than a direct skinfold-to-fat regression.

What is the best time of day and conditions for taking skinfold measurements?

Measurements should be taken in the morning, at least 2 hours after eating, and not after exercise or a hot shower (heat and exertion increase blood flow and can transiently thicken skin folds). Hydration status matters: dehydration of just 1–2% body weight can reduce skinfold readings by 5–10%. Always measure under the same conditions each time. The same technician should perform repeated assessments because inter-tester variability (~3–5%) exceeds intra-tester variability (~1–2%).

How does body fat % from skinfolds compare to BMI for health risk assessment?

BMI classifies weight relative to height but cannot distinguish fat from muscle. A muscular 90 kg athlete may have a BMI of 27 (overweight) but only 12% body fat. Conversely, a 'normal-weight' sedentary person (BMI 22) could carry 27% body fat — a condition called normal-weight obesity or 'skinny fat,' associated with metabolic syndrome. The NIH and ACSM recognize that body fat percentage is a more direct health-risk indicator than BMI, particularly for athletes and older adults with reduced muscle mass.

What body fat percentages are considered healthy by major health organizations?

The American Council on Exercise (ACE) defines healthy ranges as 18–24% for men and 25–31% for women. The WHO and NIH use similar thresholds, with obesity defined at ≥25% (men) and ≥32% (women). Essential fat — the minimum needed for physiological function — is 2–5% (men) and 10–13% (women). Competitive athletes typically fall in the 6–13% (men) and 14–20% (women) ranges. Going below essential fat levels risks hormonal disruption, bone loss, and immune suppression.

How often should I retest to track progress?

Most exercise scientists and ACSM guidelines recommend retesting every 4–8 weeks during an active fat-loss or muscle-gain program. Shorter intervals (e.g., weekly) add noise without meaningful signal, since actual body composition changes at 0.25–0.5 kg of fat per week at best. To minimize variability, always use the same technician, caliper, time of day, and hydration status. A change of ≥2–3% body fat is generally considered physiologically meaningful and outside the method's error margin.

Sources & references

Methodology & trust

Editorial

Calculadora de deportes revisada por el equipo editorial de Hacé Cuentas, contrastada con NIH — Body Composition Assessment Methods (National Library of Medicine / PubMed), según nuestra política editorial y metodología.

Updates

Última revisión: June 20, 2026. Los parámetros se verifican periódicamente con las fuentes citadas.

Privacy

Calculations run 100% in your browser. We do not store or transmit your data.

Limitations

Indicative results. For critical decisions, consult a professional.

📌 How to cite this calculator

Rodríguez, M. (2026). Body Fat % Calculator by Skinfolds. Hacé Cuentas. https://hacecuentas.com/body-fat-skinfolds-jackson-pollock

Contenido bajo licencia CC-BY 4.0 — reutilizable citando la fuente con enlace a Hacé Cuentas.

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