Modeling gas-extraction processes carried out at temperatures and pressures slightly above the critical temperature and pressure of the supercritical solvent requires equations of state (EOS) that correctly reproduce the critical temperature and pressure of the solvent. EOS that are based on statistical mechanics instead of on simple van der Waals theory are known to be superior at high densities, as encountered in gas-extraction processes. But most of these EOS overpredict the critical temperature and pressure of pure compounds significantly, if conventional pure-component parameter determination methods are applied. Here, a universal pure-component parameter determination method is proposed that enforces the correct reproduction of a pure compound＇s critical temperature and pressure. This guarantees qualitatively correct calculation results for mixtures in the region important for gas-extraction processes. This method reduces the number of adjustable pure-component parameters by two, compared to conventional methods, and enables the determination of unique parameter sets that describe a component best. Based on this method, the abilities of 12 EOS to reproduce experimentally determined densities and vapor pressures of 6 nonpolar compounds are compared.