Small orifices are widely used in different industries including gas appliances. Although characteristics of orifices such as their coefficient of discharge have been subject of interest for the past several decades, most of the previous studies focus on relatively high Reynolds number flow through relatively large diameter orifices. Moreover, the majority of previous work has focused on incompressible flows. This study focuses on the flow of different compressible gaseous fluids inside small orifices ranging from 1.3 mm to 2.1 mm hydraulic diameters for flow Re numbers of ∼8000 to ∼26000. Large-Eddy Simulation for turbulent flow is employed to solve the second-order discrete equations for compressible and incompressible flows in gas appliance orifices to predict the flow characteristics for relatively low-Re compressible flows in orifices widely used in gas appliance industry. The impacts of fluid material, the orifice hydraulic diameter, and the orifice profile on the characteristics of orifice are studied.