Material fluid permeability is an essential quality measurement in a variety of industries including textiles and papermaking. Permeability in itself is related to the porosity, density, and thickness of a material. Consistency of these material properties over time is required within a process as an indication of the quality. The purpose of permeability measurement is to accurately indicate the quality and consistency of a material product. This invention is directed to a device and method for measuring the permeability of sheet-like membranes, such as paper and textiles, that provides accurate measurements by eliminating the influence of temperature, air density, humidity, and other environmental factors. The device measures the pressure differential between a first stream of fluid applied across a test sample and a second stream of fluid applied across a sample of known permeability. Data obtained from pressure and flow rate for test and reference fluids are used to calculate percent change and actual permeability.