Linear regression was carried out using the scikit-learn package. The necessary scripts and instructions are available from GitHub repository, and the coordinate files and log files corresponding to the post-SCF DFT energy for QM9 molecules can be downloaded from DTU Data. Finally, we applied the correction method to three multi-step and single-step reactions. The error correction applied to these reactions outside the database can be regarded as an out-of-distribution test set. For the application part, we applied the correction coefficients obtained from post-SCF DFT data to correct the reaction energies from both post-SCF and SCF methods. The log files from the DFT calculations of these few test reactions are provided as supporting information. The G4MP2 energies of the molecules in the application reactions were calculated using Guassian16 43 software package.