In this paper with the help of different empirical models we have estimated the value of monthly average global solar irradiation for Ranchi (23.3500°N, 85.3300°E), a tropical location. The values of monthly average global solar radiation are calculated using the regression constants in the models (both linear and quadratic) suggested by: Angstrom Prescott, Rietveld, Ogleman, Akinoglu, Glover, Gopinathan and Sangeeta et al. All the regression models are investigated, validated and compared. On comparison it was observed that the quadratic models are overall more accurate for calculating the Global Solar Radiation for the Jharkhand region, but the Angstrom-Prescott model as well shows better variance for most of the months. The calculated data from these models is compared with the data provided by MNRE [1]. GSR values are important parameters for designing any Solar Power Systems as the whole solar power generation is directly proportional to the amount of global solar radiation. The calculated and measured data are simulated using MATLAB.