The shock stand-off distance of sphere in carbon dioxide (CO2) flow is numerically evaluated using computational fluid dynamics, with a focusing on obtaining a predictive formula based on Mach number variation. Accurate estimation of the shock stand-off distance is essential for the aerodynamic and thermal design of vehicle entering CO2-rich atmosphere such as that of Mars. The CFD simulations are carried out based on axisymmetric over a range of Mach numbers, incorporating the thermochemical nonequilibrium effects. Throughout the study, the influence of chemical reaction parameters related to carbon dioxide dissociation is also examined. It is observed that chemical reactions only slightly alter the shock stand-off distance; however, the chemical parameters significantly affect the peak temperature behind the shock. The computed shock stand-off distances are compared with empirical correlations commonly applied to Earth's atmosphere. Among these, a simple correlation based on the density ratio across the shock shows particularly good agreement with the CFD results under CO₂ hypersonic flow conditions.