We performed GCMC simulations using the RASPA2 simulation package for calculating CO2 and CH4 uptake in the 7,330 "ultrastable" MOF structures with computed mechanical properties from the USMOF DB. We measured each gas uptake at two different pressures, and the working capacity was obtained by subtracting the uptake at low pressure from the uptake at high pressure. The pressure range for CH4 was between 5.8 bar and 65 bar and CO2 was between 0.15 bar and 16 bar, which were chosen based on the standard CH4 and CO2 adsorption and desorption pressures . The temperature was kept at 298 K and a rigid framework assumption was used for all gas uptake simulations. All simulations comprised 5,000 initialization cycles followed by 5,000 equilibration cycles. From all attempted calculations, 385 calculations failed or took longer than 48 hours, leaving 6,945 MOFs after all properties (i.e., mechanical stability, framework charge, and gas working capacity) calculated (Figure ).