7 Site Skinfold Calculator – Measure Jackson And Pollock 7-site Skinfold

The 7-site skinfold calculator is a sophisticated tool used by fitness professionals and researchers to assess body composition and estimate body fat percentage.

Unlike simpler methods like BMI or basic body fat scales, the 7-site method provides a more comprehensive assessment by accounting for fat distribution patterns across different body regions. Research has shown this method to be accurate within 1-3% when performed correctly by trained professionals.

7 Site Skinfold Calculator

Age	Gender	Sum of Skinfolds	Body Density	Body Fat %
30	Male	110mm	1.0654	14.6%
25	Female	125mm	1.0423	24.8%
40	Male	150mm	1.0512	19.2%
35	Female	140mm	1.0387	26.4%
28	Male	120mm	1.0610	16.5%
32	Female	130mm	1.0450	22.5%
45	Male	160mm	1.0485	21.0%
38	Female	135mm	1.0400	25.0%
50	Male	170mm	1.0420	23.5%
27	Female	115mm	1.0500	20.0%
33	Male	140mm	1.0545	18.3%
29	Female	128mm	1.0460	22.0%
42	Male	155mm	1.0498	20.3%
36	Female	145mm	1.0395	27.2%
48	Male	165mm	1.0467	22.8%
31	Female	122mm	1.0438	23.3%

What is 7 Site Skinfold?

The 7-site skinfold measurement refers to the precise assessment of subcutaneous fat thickness at seven standardized anatomical locations

The 7-site skinfold measurement involves taking precise measurements at these key anatomical locations:

• Chest (diagonal fold at the midaxillary line)
• Midaxillary (vertical fold on the midaxillary line at nipple level)
• Triceps (vertical fold on the posterior midline of the upper arm)
• Subscapular (diagonal fold at inferior angle of the scapula)
• Abdominal (vertical fold 2cm right of the umbilicus)
• Suprailiac (diagonal fold above the iliac crest)
• Thigh (vertical fold at the anterior midline of the thigh)

Each measurement requires careful technique, including:

• Grasping the skinfold firmly between thumb and forefinger
• Placing caliper perpendicular to the fold
• Taking readings within 1-2 seconds of caliper placement
• Recording measurements to the nearest 0.5mm

Seven Site Skinfold Formula

The Jackson-Pollock formula is the most widely used equation for calculating body density from 7-site measurements. The formula varies by gender:

For Men:

Body Density = 1.112 - (0.00043499 × sum of skinfolds) + 
(0.00000055 × square of the sum of skinfolds) - 
(0.00028826 × age)

For Women:

Body Density = 1.097 - (0.00046971 × sum of skinfolds) + 
(0.00000056 × square of the sum of skinfolds) - 
(0.00012828 × age)

To convert body density to body fat percentage, use the Siri equation:

Body Fat % = (495 / Body Density) - 450

How to Calculate 7 Site Skinfold Body Fat?

The calculation process involves several systematic steps:

• Measurement Collection:
  • Take measurements in millimeters
  • Perform each measurement 2-3 times
  • Use the average of measurements
  • Ensure consistent technique
• Data Input:
  • Sum all seven measurements
  • Record age and gender
  • Apply appropriate formula

Let’s walk through a practical example:

Consider a 30-year-old male with these measurements (in mm):

• Chest: 15
• Midaxillary: 12
• Triceps: 10
• Subscapular: 17
• Abdominal: 25
• Suprailiac: 18
• Thigh: 13

Step 1: Sum all measurements

Total = 110mm

Step 2: Apply the Jackson-Pollock formula

Body Density = 1.112 - (0.00043499 × 110) + 
(0.00000055 × 110²) - (0.00028826 × 30)
= 1.0654

Step 3: Convert to body fat percentage using Siri equation

Body Fat % = (495 / 1.0654) - 450 = **14.6%**

References:

• American College of Sports Medicine (ACSM) – https://www.acsm.org/
• National Strength and Conditioning Association (NSCA) – https://www.nsca.com/

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