Data-driven offshore CO2 saline storage assessment methodology

•The tailored methodology accounts for changes in CO2 density and sediment behavior.•The calculator accounts for unique offshore features (i.e., water depths).•Domain storage estimates ranged from 0.5 to 10,000 Gigatons of CO2.•Saline efficiency was a significant factor when calculating storage capacity.•The methodology and calculator are applicable at multiple geographic scales.