The paper discusses the issues of improving the calculation methods and designs of linear-driven compressors operating on gas mixtures. The results of numerical analysis of the operation of a linear-driven piston compressor stage with a variable cylinder diameter in the range of from 90 to 200 mm are presented. The study was carried out on the basis of various modifications of the approved KOMDET-VKA software. In numerical analysis, a hydrogen-containing mixture was adopted as the working substance. It is proved that the isothermal indicator and mechanical efficiency of the compressor are increased by 2 and 4%, respectively, as the cylinder diameter of the stage increases in a given range.