Site Insertion Loss (SIL) measurements are performed to validate antenna calibration sites as per CISPR 16-1-5 by using calculable dipole antennas. The validation process first requires the production of theoretical SIL values based on dimensions of dipole antennas employed, three-port balun S parameters, the condition of the ground floor, and the measurement geometry such as antenna heights, measurement distance and polarization. In this paper, we developed and proposed a user-friendly and useful software solution that can calculate theoretical SIL values by using three-port balun S parameters and entered parameters for any desired measurement geometry. Following this, we compared the theoretical SIL results of the proposed software with a well-known software solution referenced in CISPR 16-1-5 in a variety of SIL geometries for validation purposes and the advantages of the proposed software solution are demonstrated. Ultimately, we verified our new calculable dipole antennas at close distance in our anechoic chamber by using theoretical SIL values produced by the proposed software solution.