Skinfold Body Fat Calculator

How to calculate Skinfold Body Fat Calculator?

This method converts four skinfold measurements into body density using the Durnin-Womersley approach, then converts density to percent body fat with the Siri equation.

Body Density = c - m × log10(sum of 4 skinfolds) (c and m depend on age and sex); Body Fat % = (495 / Body Density) - 450

Using the Skinfold Body Fat Calculator calculator: an example

Example measurements: Triceps 12 mm, Biceps 8 mm, Subscapular 10 mm, Suprailiac 14 mm.

Step-by-step calculation:

1. Sum the four skinfolds: 12 + 8 + 10 + 14 = 44 mm.
2. Compute log10 of the sum: log10(44) ≈ 1.643.
3. Apply the Durnin-Womersley formula (example male constants): Body Density ≈ 1.1599 - 0.0717 × 1.643 ≈ 1.042 g/ml.
4. Convert to body fat percentage using Siri: Body Fat % ≈ (495 / 1.042) - 450 ≈ 25.1%.

Frequently Asked Questions

How accurate is the skinfold method?

When measured correctly by a trained technician, skinfold estimates are generally within ±3-5% of laboratory methods; errors increase with poor technique.

Do I need to adjust for age and sex?

Yes. The Durnin-Womersley equations use different constants for age groups and sex, so apply the appropriate set for best accuracy.

Can I take these measurements at home?

You can, but accuracy improves with practice or when performed by someone experienced; use proper calipers and follow standard landmark instructions.