# Equations: Jackson & Pollock

Here are several equations that give a value for body density and percent body fat from skinfold and girth circumference test results, from the research of Dr. Andrew Jackson and M. L. Pollock. The original source reference is given where known.

Once the body density is calculated using the equations below, the level of percent bodyfat (%BF) can be determined using the Siri Equation. See more equations for measuring body fat using skinfold measures.

## PERCENT BODY FAT

## Males

### 4-Site Skinfold Equation (for calculating % body fat)

% Body Fat= (0.29288 x sum of skinfolds) – (0.0005 x square of the sum of skinfolds) + (0.15845 x age) – 5.76377, where the skinfold sites (measured in mm) are abdominal, triceps, thigh and suprailiac

## Females

### 4-Site Skinfold Equation

% Body Fat= (0.29669 x sum of skinfolds) – (0.00043 x square of the sum of skinfolds) + (0.02963 x age) + 1.4072, where the skinfold sites (measured in mm) are abdominal, triceps, thigh and suprailiac

### 3-Site Skinfold Equation

% Body Fat= (0.41563x sum of skinfolds)– (0.00112x square of the sum of skinfolds) + (0.03661 x age) + 4.03653, where the skinfold sites (measured in mm) are abdominal, triceps and suprailiac

## BODY DENSITY

## Males

### Equation includes girth measurements

Body Density= 1.0990750 - 0.0008209 (X_{2}) + 0.0000026 (X_{2})^{2}- 0.0002017 (X_{3}) - 0.005675 (X_{4}) + 0.018586 (X_{5}). Where X_{2}= sum of the chest, abdomen and thigh skinfolds in mm, X_{3}= age in years, X_{4}= waist circumference in m, and X_{5}= forearm circumference in m.

### 3-Site Skinfold Equation

Body Density= 1.1125025 - (0.0013125 x sum of chest, triceps and subscapular skinfolds in mm ) + (0.0000055 x square of the sum of chest, triceps and subscapular) - (0.000244 x age)

### 3-Site Skinfold Equation

Body Density= 1.10938 - (0.0008267 x sum of chest, abdomen and thigh skinfolds in mm ) + (0.0000016 x square of the sum of chest, abdomen and thigh) - (0.0002574 x age)

### 7-Site Skinfold Equation

Body Density= 1.112 - (0.00043499 x sum of skinfolds) + (0.00000055 x square of the sum of skinfold sites) - (0.00028826 x age), where the skinfold sites (measured in mm) are: Chest, Axilla, Tricep, Subscapular, Abdominal, Suprailiac and Thigh

## Females

### Equation that includes girth measurements

Body Density= 1. 1470292 - 0.0009376 (X_{3}) + 0.0000030 (X_{3})^{2 }- 0.0001156 (X_{4}) - 0.0005839 (X_{5}), Where: X_{3}= sum of triceps, thigh and suprailiac skinfolds, in mm, X_{4}= age in years and X_{5}= gluteal circumference in cm.

### 3-Site Skinfold Equation

Body Density= 1.0994921 - (0.0009929 x sum of triceps, thigh and suprailiac skinfolds) + (0.0000023 x square of the sum of triceps, thigh and suprailiac skinfolds) - (0.0001392 x age)

### 7-Site Skinfold Equation

Body Density= 1.097 - (0.00046971 x sum of skinfolds) + (0.00000056 x square of the sum of skinfold sites) - (0.00012828 x age), where the skinfold sites (measured in mm) are: Chest, Axilla, Tricep, Subscapular, Abdominal, Suprailiac and Thigh

## References

- Jackson, A. S., & Pollock, M. L. (1978).
*Generalized equations for predicting body density of men.***British Journal of Nutrition**, 40, 497-504. - Jackson, A. S., Pollock, M. L., & Ward, A. (1980).
*Generalized equations for predicting body density of women.***Medicine and Science in Sports and Exercise**, 12, 175-182. - Jackson A S, Pollock, M (1985) Practical assessment of body composition.
**Physician Sport Med**. 13: 76-90

## Related Pages

- More on body density
- About calculating percent bodyfat
- Formulas for calculating % Bodyfat - skinfold method
- norms for %bodyfat levels for athletes and the general population
- Skinfold Measures
- A discussion about Body Composition Testing
- Videos of Anthropometric Tests including Skinfold Testing.
- skinfold caliper store

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