Collects results of highly accurate QM (quantum mechanics) calculations of molecular structures, energies and properties. BEGDB hosts data which can serve as benchmarks for testing and parameterization of other computational methods. In BEGDB, data are organized into datasets that contain the result from separate publications. More details, including full citation and link to the original paper are accessible from the listing of the datasets using the Details link. All the data displayed in the results table can be downloaded in comma-separated values (CSV) format and geometries of the molecules/systems can be downloaded as a single zip archive.