Orifice Meters are mechanical devices used to measure gases and liquids flows. Due to manufacturing, installation and operation simplicity, the orifice meters are widely used in the industrial processes in which there is flow of gases or liquids. Moreover, their acquisition and operation costs are smaller than the ones verified for other flow meters (Venturi, flowmeter). However, before the utilization of any calibration orifice meters, they demand an experimental calibration procedure. Thus, in order to suppress this laborious experimental procedure, this work objectified to apply computational fluid dynamics techniques (CFD) to numerically predict the Calibration Coefficient of the orifice meter. The adopted numerical methodology was able to satisfactorily predict the discharge coefficients, presenting an economic alternative when compared to traditional experimental approaches.