This study was designed to estimate the optimized conditions for the computational study of quantum characteristics of beta blockers. Carvedilol was selected as a representative of beta blockers. Optimized energies and bonds lengths were measured using different methods including PM3, HF and DFT. A comparison has been made between Gaussian and GAMESS programs. The difference in optimized energy values, and the a pproaching of the bonds angle to the optimal values were studied. The results showed that Gaussian software showed higher priority than GAMEES software, which can be obbserved from the differences in the optimized energy values and the approaching of the bonds angles to the optimal values. the obtained results will bedepeneded in all subscuent studies. IR spectroscopic data were employed to select the most appropriate method. three different methods (PM3, HF and DFT) have been used to measure IR, then compared with experimental values of carvedilol. DFT method showed an advantage over the other methodsBased on all above, DFT (B3LYP/6-311G) has been recommended in the computational chemistry calculations study for carvedilol and resemble beta blockers.