The corrections to the error in DFT energy with respect to the G4MP2 energy for each bond is provided in Table . The maximum value (≥0. The accuracy of the three different DFT functionals follows the complexity/accuracy trade-off along Jacob's ladder. PBE is a GGA type functional without any fit to molecular properties. Hence, the errors in energy from PBE are systematic. B3LYP-D is a hybrid functional and is two rungs higher than PBE. It is parameterized against the main group elements, and the errors are expected to be smaller and of a more random nature. Before the correction, the MAE is reduced from 0.145 eV to 0.134 eV (PBE to B3LYP-D) however, after correction, the MAE becomes 0.076 and 0.082 eV for PBE and B3LYP-D respectively. The M06-2X falls into the category of hybrid meta-GGA functional and it is highly parameterized against a very accurate wide variety of datasets. Hence, it is expected to be more accurate than both B3LYP and PBE. That is evident from the reduction of the MAE to reaction energy to 0.110 eV before correction. Due to parameterization, errors from M06-2X are also randomized. The correction models perform better for PBE than for functionals that are parameterized, i.e., B3LYP-D, and M06-2X. The improvement of the MAE to the reaction energies using the bond-based correction method as a function of molecular size is given in Figure . The uncorrected error in PBE and B3LYP-D functionals increases with system size while that for M06-2X is size-independent.