Filtration media including woven cloths, nonwoven, membranes and particulate beds are used in a wide variety of applications such as biotech, health care, pharmaceutical, food and beverages, power sources and chemical industries. One way to characterise the performance of all these filtration media is by the pore structure characteristics of the media. Several experimental techniques are available to measure such characteristics, each of them producing a different outcome. Having the aim to find the optimal design of filtration media with numerical simulations, it is necessary to be able to predict the outcome of pore size measurements as this allows a comparison of virtually created filtration media with existing filtration media. This paper focusses on the numerical simulation of mercury intrusion porosimetry and liquid extrusion porosimetry. First, the numerical method will be introduced and applied on a sample nonwoven. Results of both methods will be presented and related to the real pore structure of the medium. Afterwards, the influence of a change in a single production parameter on the pore distribution will be investigated exemplarily. Finally - to validate the method ~ the numerical results will be compared with experimental findings.