Skinfold Body Fat Calculator

Body fat percentage from caliper measurements using the Jackson–Pollock 3-site method.

Sex
yrs
mm
mm
mm

Take each fold on the right side of the body with calipers, twice, and use the average.

What is the skinfold (caliper) method?

This skinfold body fat calculator uses the Jackson–Pollock 3-site method — the most widely used caliper protocol in fitness testing. Pinch three sites with calipers, enter the millimetre readings, and it estimates your body fat percentage. In practised hands it's one of the most accurate field methods available.

How it works

Skinfold thickness reflects subcutaneous fat, which tracks total body fat predictably. The sites differ by sex — chest, abdomen and thigh for men; triceps, suprailiac (above the hip bone) and thigh for women. The sum of the three folds and your age go into the Jackson–Pollock body-density equations, and density converts to body fat percentage via the Siri equation (495/density − 450). The original studies validated these equations against hydrostatic weighing in over 400 adults.

How to measure correctly

  • All folds on the right side of the body, skin dry, not post-workout
  • Pinch firmly with thumb and finger, place calipers 1 cm below the fingers, read after two seconds
  • Take each site twice and average; re-measure if readings differ by more than 2 mm
  • Same conditions every time — consistency beats precision

Frequently asked questions

How accurate are calipers?

With good technique, about ±3–5%. Most of the error is the tester, not the tool — which is why your trend across weeks (same tester, same conditions) is much more reliable than any single reading.

Calipers or the tape method?

Both land in a similar accuracy range. Calipers are better at tracking small changes in leaner people; the Navy tape method needs no skill and no second person. Choose the one you'll actually do consistently.

References

  1. Jackson AS, Pollock ML. Generalized equations for predicting body density of men. Br J Nutr. 1978;40(3):497–504.
  2. Jackson AS, Pollock ML, Ward A. Generalized equations for predicting body density of women. Med Sci Sports Exerc. 1980;12(3):175–181.
  3. Siri WE. Body composition from fluid spaces and density. In: Techniques for Measuring Body Composition. National Academy of Sciences; 1961:223–244.

Related

These results are estimates for healthy adults and are not medical advice. Consult a health professional before making major changes to your diet or training.

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