Using Griddler software, this study aims to select the optimal metallization design by analyzing the impact of the number and sizes of busbars and fingers on a solar cell’s performance. There is interest in the PV industry to reduce the finger size toward 25 μm in upcoming years. It is shown that an increase in the number and size of busbars and fingers causes an increase in the fill factor; however, with regards to the cell’s efficiency, the shading factor should be considered in addition to the size and number of metal contacts. The results of this study indicate that solar cells’ efficiency could be increased by 0.33–0.84% when using five busbars and a finger width of 35 μm. Moreover, this increase is achieved by reducing the emitter resistance to less than 60 ohm/sq and considering a recombination rate of about 165 fA/cm2.