Relevance. Currently, the market for specialized software is dominated by Western products that allow for the calculation of phase equilibria of hydrocarbon mixtures "in one click" by simply specifying the composition of the hydrocarbon mixture and the thermobaric conditions. Russian counterparts often lack sufficient functionality to perform accurate calculations, including scientific ones. Moreover, existing software packages do not always provide representative results at high pressures or in conditions close to critical. Aim. High-performance calculations of phase equilibrium for gas-condensate mixtures across a wide range of pressures and temperatures. Results and key findings. This work provides a detailed description of phase equilibrium calculations based on the Soave–Redlich–Kwong state equation with the Peneloux correction across a wide range of specified thermobaric conditions. The authors give the recommendations implementing a stability check algorithm to improve the initial approximation of Wilson constants. The authors identified the coefficients for the sequential approximation algorithm, enhancing its convergence speed. Software modules were developed for calculating mole fractions, as well as the composition of vapor and liquid phases, based on data about the mixture composition, pressure, and temperature, in four programming languages. Results on the computational speed of the algorithm on graphics processing units are presented for Python, Matlab, and Go. It is shown that the implementation of a parallel phase equilibrium calculation algorithm for multiple calculation points on a graphics processing unit using C++ CUDA reduces computation time by 200 times without loss of accuracy.