While Louvreclad does have options that provide this, it is important to understand that there are a number of different methods and standards within the industry for measuring Free Open Area (FOA),  all of which will give you very different results.

Alongside this, FOA does not tell you anything about the aerodynamic or the rain defence performance of the louvre profile. Therefore, FOA is not necessarily the best way to measure louvre performance. (Please see Louvreclad white paper for further info)

Ultimately, it is better to check that the louvre is tested to AS/NZS 4740:2000, the Australian Standard for testing natural ventilators