A new experimental model based on the geometric parameters of a woven structures yarn linear density and fabric tightness has been developed to predict the volume porosity of woven fabrics. The experimental model is based on a factor analysis. Experiments involve fabrics made from staple yarns, but the mathematical model of volume porosity can also be applied to fabrics made from mono- or multifilament yarns. The experimental results of volume porosity correspond very well with calculated values according to the proposed equation.