The Fitties Journal
How to Calculate Body Fat with the Jackson-Pollock 7 Body Fat Formula
Key Takeaways
Here's what matters most if you're short on time:
- The JP 7-site method measures seven locations (chest, midaxillary, tricep, subscapular, abdomen, suprailiac, thigh), all the same for both males and females.
- More measurement sites produce a more accurate body fat estimate by capturing a broader picture of fat distribution across the body.
- This method requires a partner for several sites (subscapular, midaxillary) and takes more time than the 3- or 4-site versions, but the tradeoff is the most accurate estimate in the JP family.
The Jackson-Pollock 7-site body fat test, developed in 1978 by Dr. Andrew Jackson and M. L. Pollock, is the most comprehensive method in the JP family. It uses seven skinfold measurements to estimate body fat percentage, providing a more detailed picture of fat distribution than the 3-site or 4-site methods.
The logic is straightforward: more measurement sites means more data points, which means a more accurate estimate. The tradeoff is time and the need for a partner, since several of the seven sites are difficult to reach on your own. For anyone willing to invest the extra few minutes per session, the JP 7-site method delivers the most reliable result in the JP lineup.
For a complete overview of all body fat measurement methods and how to use calipers, see our guide to measuring body fat.
Who Is This Method For?
The JP 7-site method is ideal for anyone who wants the most accurate caliper-based estimate available within the JP framework and has a partner to help with measurements. It is widely used by personal trainers, fitness professionals, and individuals who are serious about tracking body composition changes over time.
Like the other JP formulas, this method was developed for the general population. It may underestimate body fat in very lean or highly trained individuals. If you are a competitive athlete, the Yuhasz method was designed specifically for athletic populations. If you want even more measurement sites, the Parillo method uses nine.
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Shop FitFightSkinfold Measurement Locations (Males and Females)
All seven measurement sites are the same for both males and females.
| Site | Location | Fold Direction |
|---|---|---|
| Chest (Pectoral) | Between the nipple and the armpit, one-third of the way closer to the armpit, following the nipple-armpit line | Diagonal |
| Midaxillary | Side of the torso at the level of the fifth rib, directly below the armpit. Raise arm to chest height when measuring. | Horizontal or Vertical |
| Tricep | Halfway between the top of the shoulder and the elbow, on the back of the arm | Vertical |
| Subscapular | Approximately 2 cm below the bottom tip of the shoulder blade, at a 45-degree angle parallel to the inner angle of the shoulder blade | Diagonal (45°) |
| Abdomen | One inch to the right of the belly button | Vertical (preferred) or Horizontal |
| Suprailiac | Approximately two inches above the iliac crest (upper protrusion of the hip bone), between the top of the hipbone on the side of the body and the front of the hipbone | Diagonal (45°) |
| Thigh | Front of the quadriceps, halfway between the top of the knee and the fold at the top of the thigh | Vertical |
Jackson-Pollock 7-Site Formula for Males
Measure the following skinfolds in millimeters with body fat calipers: Chest, Midaxillary, Tricep, Subscapular, Abdomen, Suprailiac, and Thigh.
| Step | Formula |
|---|---|
| Body Density | 1.112 - (0.00043499 x sum of skinfolds) + (0.00000055 x sum of skinfolds²) - (0.00028826 x age) |
| Body Fat % | (495 / Body Density) - 450 |
Jackson-Pollock 7-Site Formula for Females
Measure the following skinfolds in millimeters with body fat calipers: Chest, Midaxillary, Tricep, Subscapular, Abdomen, Suprailiac, and Thigh.
| Step | Formula |
|---|---|
| Body Density | 1.097 - (0.00046971 x sum of skinfolds) + (0.00000056 x sum of skinfolds²) - (0.00012828 x age) |
| Body Fat % | (495 / Body Density) - 450 |
Example Calculation
Here is a worked example for a 35-year-old male with the following skinfold measurements:
| Site | Measurement |
|---|---|
| Chest | 10 mm |
| Midaxillary | 14 mm |
| Tricep | 12 mm |
| Subscapular | 16 mm |
| Abdomen | 22 mm |
| Suprailiac | 18 mm |
| Thigh | 15 mm |
| Sum of Skinfolds | 107 mm |
Step 1: Calculate Body Density
Body Density = 1.112 - (0.00043499 x 107) + (0.00000055 x 107²) - (0.00028826 x 35)
Body Density = 1.112 - 0.046544 + 0.006293 - 0.010089
Body Density = 1.06166
Step 2: Convert to Body Fat Percentage
Body Fat % = (495 / 1.06166) - 450
Body Fat % = 466.34 - 450
Body Fat % = 16.3%
Tips for Accurate Results
Always measure from the right side of the body. The JP 7 formulas were developed using right-side measurements. Switching sides introduces inconsistency.
Take two measurements at each site. If the two readings differ by more than 2 mm, take a third. Use the average of the two closest readings. With seven sites, small errors at each location can compound, so this step matters more than with the 3- or 4-site methods.
Rotate through all seven sites before remeasuring. This gives the skin time to return to its normal thickness between pinches at the same location.
Measure before exercise. Post-workout blood flow temporarily increases muscle size and alters skinfold thickness, particularly at the chest, midaxillary, and thigh sites.
Use the same calipers and the same tester every time. With seven sites, inter-tester and inter-instrument variation has a larger cumulative effect on the final result. Consistency in both is critical.
Pay attention to the thigh site. Skin and fat in the quadriceps area tend to be firmer, which can make pinching more difficult. A firm, consistent pinch is important. If you find the thigh reading varies more than other sites, take three measurements there routinely.
How the JP 7-Site Compares to Other Methods
| Method | Sites | Best For |
|---|---|---|
| JP 3-Site | 3 | Quick estimate, beginners, solo measurement |
| JP 4-Site | 4 | Same sites for both genders, good accuracy-to-effort ratio |
| JP 7-Site (this article) | 7 | Most comprehensive JP method, fitness professionals |
| Durnin-Womersley | 4 | Broad age range (16-72), age-specific equations |
| Yuhasz | 6 | Athletes and highly fit individuals |
| Parillo | 9 | Most detailed caliper method |
Supporting Your Body Composition Goals
The JP 7-site method gives you the most detailed caliper-based body fat data in the Jackson-Pollock family. Pairing that data with the right nutritional support helps you act on what the numbers tell you.
FitFight contains key amino acids (5-HTP, DL-Phenylalanine, L-Tyrosine, L-Glutamine) alongside chromium to support the biosynthesis of neurotransmitters involved in appetite control and mood. Chromium is present to support healthy glucose metabolism and food intake regulation.
Conclusion
The Jackson-Pollock 7-site method is the most thorough option in the JP lineup. Seven measurement sites, same locations for both genders, and a formula that has been validated across decades of use in fitness and clinical settings. It takes a few more minutes than the 3- or 4-site methods and requires a partner for several sites, but the improved accuracy is worth it for anyone who is serious about tracking body composition.
If seven sites feels like more than you need, the JP 4-site method offers a solid accuracy-to-effort balance. If you want even more detail, the Parillo method uses nine sites. And if you are a competitive athlete looking for a formula designed for your population, the Yuhasz method is worth a look.
FitFight
FitFight contains key amino acids (5-HTP, DL-Phenylalanine, L-Tyrosine, L-Glutamine) alongside chromium to support the biosynthesis of neurotransmitters involved in appetite control and mood. Chromium supports healthy glucose metabolism and food intake regulation. 240 vegetarian capsules.
Shop FitFight
