Chest (Pectoral)
- Find the midpoint between the front armpit fold and nipple.
- Pinch a diagonal fold with thumb and index finger.
- Place caliper jaws 1 cm below the fingers and read after 1 to 2 seconds.
Skinfold Body Fat Calculator
Estimate body fat percentage from 3-site skinfold caliper measurements with Jackson-Pollock equations and Siri conversion.
ImperialMetric
Gender
Age
30
Weight
181 lbs
Chest (Pectoral)
12 mm
Diagonal fold midway between armpit and nipple.
Abdomen
18 mm
Vertical fold about 2 cm right of the navel.
Thigh
18 mm
Vertical fold on the front mid-thigh.
Skinfold Body Fat
14.5
% BF
Fit
Lean and sustainable for many trained adults.
Body Fat %
14.5%
Sum of 3 Sites
48 mm
Fat Mass
26.2 lbs
Lean Mass
154.6 lbs
Body Density (g/cm^3)
1.0657
Method
Jackson-Pollock 3-site + Siri equation
51015202530354045
EssentialAthleticFitAverageHighVery High
Fit
Skinfold Body Fat RangesMEN
These are practical interpretation bands for estimated body fat percentage from skinfold measurements. Use this as a trend tool, not a diagnosis.
| RANGE | CATEGORY |
|---|---|
0-6% | Essential Extremely lean and difficult to sustain for most people. |
6-14% | Athletic Lean, performance-focused range with visible definition. |
14-18% | Fit Lean and sustainable for many trained adults. |
18-25% | Average Common adult range. Trend direction matters most. |
25-32% | High Higher body-fat range. Focus on consistent habits and trend tracking. |
32+% | Very High Very high range. Prioritize sustainable routines and consistency. |
What This Skinfold Calculator Uses
This tool uses the Jackson-Pollock 3-site protocol, which estimates body density from three skinfold measurements plus age. It then converts density to body-fat percentage using the Siri equation.
Skinfold measurements estimate subcutaneous fat, not total body fat directly. Accuracy depends heavily on consistent site location and pinching technique.
Equations Used
The calculator applies sex-specific Jackson-Pollock 3-site equations:
Men (sites: chest, abdomen, thigh)
Density = 1.10938 - 0.0008267 x S + 0.0000016 x S^2 - 0.0002574 x Age
Women (sites: triceps, suprailiac, thigh)
Density = 1.0994921 - 0.0009929 x S + 0.0000023 x S^2 - 0.0001392 x Age
Siri conversion
%Body Fat = (495 / Density) - 450
In the equations above, S is the sum of the three skinfold measurements in millimeters.
How To Measure Skinfold Sites
For better consistency, always measure on dry skin, hold the pinch while reading the caliper, and average at least 2 to 3 readings per site.
Men: 3-Site Protocol
Abdomen
- Locate a point about 2 cm to the right of the navel.
- Lift a vertical skinfold away from the abdominal wall.
- Apply calipers and record the reading in millimeters.
Thigh
- Measure on the front of the thigh midway between hip and kneecap.
- Keep body weight on the opposite leg to relax the measured thigh.
- Pinch a vertical fold and read with calipers.
Women: 3-Site Protocol
Triceps
- Mark the midpoint between shoulder and elbow on the back of upper arm.
- Lift a vertical skinfold at the marked site.
- Apply calipers 1 cm below fingers and read after 1 to 2 seconds.
Suprailiac
- Find the area just above the iliac crest on the side of the waist.
- Pinch a diagonal fold following the natural skin line.
- Place calipers below fingers and log the mm reading.
Thigh
- Measure on the front of thigh halfway between hip and kneecap.
- Keep leg relaxed and pinch a vertical fold.
- Take the caliper reading after 1 to 2 seconds.
Accuracy and Limitations
Skinfold calipers can be useful when technique is consistent, but results vary with tester experience, caliper quality, and hydration status. Small placement differences can shift your estimate.
Use skinfolds as a trend metric. If the protocol and measurer stay consistent, direction over time is often more useful than one absolute value.
For comparison, check the Navy Body Fat Calculator and Army Body Fat Calculator plus the BRI Calculator for waist-centered roundness context, or the BAI Calculator for hip-height adiposity.
References
- Jackson AS, Pollock ML. Generalized equations for predicting body density of men.PubMed record
- Jackson AS, Pollock ML, Ward A. Generalized equations for predicting body density of women.PubMed record
- Ackland TR, et al. Current status of body composition assessment in sport and exercise.PubMed record