A parametric study was conducted on small scale, subsonic Venturi nozzles. The purpose of this study was to determine the effect of different operating conditions and different geometric parameters on the performance of the nozzle. In this study, the performance of the nozzle was defined as the ratio of suction mass flow to motive mass flow, or the suction ratio. The parametric study included 15 different nozzle geometries, under various operating conditions, for a total of 55 case studies. The parametric study was conducted using CFD in Ansys Fluent. Additionally, experimental validation was conducted for several 3D printed nozzles. Dimensional analysis of the parameters was completed to determine the form of a dimensionless correlation for the suction ratio as a function of the other parameters. The case studies were run through a constrained multi-variable global optimization code to determine the dependency on each dimensionless group. This correlation can be used as a design guide for Venturi nozzles. If operating conditions dictate an optimum suction ratio, the ideal nozzle geometry can be determined. Alternatively, based on the geometry of a given nozzle, the resulting suction ratio can be determined.