Calculate Your 3-Site Body Fat %
Use skinfold measurements in millimeters (mm). This calculator uses the Jackson-Pollock 3-site formulas and Siri equation.
What is a 3 point body fat calculation?
A 3 point body fat test estimates your body fat percentage using three skinfold measurements and your age. It is one of the most practical methods for home and gym use because it is faster than 7-site testing and more informative than scale-only methods.
The test uses different measurement sites for men and women and then applies a validated equation to estimate body density. Body density is then converted to body fat percentage with the Siri formula.
Measurement sites used in this calculator
For men
- Chest: Diagonal fold halfway between armpit and nipple.
- Abdomen: Vertical fold about 2 cm to the right of the navel.
- Thigh: Vertical fold on the front of the thigh, midway between hip and knee.
For women
- Triceps: Vertical fold on the back of the upper arm, halfway between shoulder and elbow.
- Suprailiac: Diagonal fold just above the iliac crest (hip bone), along natural skin lines.
- Thigh: Vertical fold on the front of the thigh, midway between hip and knee.
How to take accurate skinfold measurements
- Use quality skinfold calipers that read in millimeters.
- Pinch skin and subcutaneous fat, not muscle.
- Place the caliper jaws about 1 cm below your fingers.
- Read the measurement after about 1-2 seconds.
- Take 2-3 readings per site and use the average.
How to interpret your result
Your number is an estimate, not a diagnosis. Use it to monitor trends over weeks and months rather than chasing single-day precision. As a rough guideline:
- Male: Essential fat 2-5%, athletic 6-13%, fitness 14-17%, average 18-24%, obesity 25%+
- Female: Essential fat 10-13%, athletic 14-20%, fitness 21-24%, average 25-31%, obesity 32%+
Common mistakes to avoid
- Measuring different locations each time.
- Taking readings right after a hard workout.
- Using only one reading per site.
- Comparing your caliper result directly to DEXA without context.
Best way to use this calculator over time
Track every 2-4 weeks under similar conditions. Pair body fat percentage with scale weight, waist circumference, gym performance, and progress photos. A single metric can be misleading, but a group of metrics gives a much clearer picture of progress.