In this paper, the calculation of electrical properties for (n)GaP–p(Si) solar cells was performed for different contact grid design. The influence of annealing temperature on the current-voltage curves of solar cells was shown via the Hall measurements and the simulation respectively. For calculations 20 μm and 200 μm width contact bars were used. First group corresponds to lithography. The second one could be appropriate for mass-scalable screen-printing metallization technique. The distance between contacts was varied in the range from 50 μm to 4000 μm in case for 20 μm contact width and in the range from 200 μm to 4000 μm in case for 200 μm contact width. According to the results of calculation, the thermal annealing at 600–700 ˚C is optimal for 20 μm configuration of contact grid. The predicted conversion efficiency is approximately 21.5%. Relative to contact grid with 200 μm width of bars, the optimal annealing temperature is 700 ˚C. These conditions lead to 19% conversion efficiency.