The pK a data are collected from the iBonD database as well as a set of recently compiled and curated pK a data, and jointly contain 8,241 entries. We curated these data by manually examining the pK a values, checking the data for unreasonable values based on agreement between values from different sources, correlations between data in different solvents, acidity trends, and chemical feasibility. For most of these acids, we calculated their gas-phase acidities, benchmarking different levels of quantum chemical theory observed in our previous work to achieve an effective balance of computational cost and accuracy. Using the COnductor like Screening MOdel for Real Solvents (COSMO-RS) ,49 method, we computed the solvation free energies of the neutral acids, and leveraged previously-published data for the solvation free energy of the proton in both aqueous and non-aqueous solvents along with a thermodynamic cycle to obtain solvation free energies of anions.