STROBL FITNESS
Body Composition

Measure your progress.

Jackson–Pollock 3-site caliper calculator. Three measurements, one clear result.

Your details

Skinfold measurements (millimeters)

Use the same sites, side of the body, and technique each time. Enter the skinfold thickness in mm, not inches.
ESTIMATED BODY FAT
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Estimated fat mass—
Estimated lean mass—

Progress trend

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Measurement history

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This is a screening estimate, not a direct measurement of body fat. Jackson–Pollock 3-site equations estimate body density; the Siri equation converts density to body-fat percentage. At very low body-fat levels, small caliper differences can cause substantial variation. For consistency, measure under similar conditions, preferably using multiple readings per site.