Petroski skinfold calculator (4 sites)

Enter sex, age, weight and the protocol's 4 skinfolds. The calculator estimates body density with Petroski's equation, converts it to body fat percentage and shows fat and lean mass.

years
lb
To calculate fat and lean mass
Skinfolds
mm
mm
mm
mm
Body fat
17.5%
Sum of skinfolds: 51 mm
Body density
Converted to % body fat with the Siri equation
1.0588 g/cm³
Fat mass
30.1 lb
Lean mass
141.9 lb

Estimate for adults. Always use the same protocol and assessor to compare assessments.

How it works

  1. Men: subscapular, triceps, suprailiac and medial calf.
  2. Women: midaxillary, suprailiac, thigh and medial calf.
  3. Petroski's equation (1995) estimates body density from the sum of skinfolds and age.
  4. Density is converted to body fat percentage with the Siri equation (1961).

FAQ

Why use Petroski?

The equations were developed and validated with Brazilian adults. For other populations, Jackson-Pollock is the more widely used reference.

Can I compare it with a Jackson-Pollock assessment?

Not directly. Different protocols give different estimates. Always compare assessments done with the same protocol.

In Trainer Fácil, every assessment is saved to the client's profile so you can compare progress month by month.

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