The aim of the study was to evaluate the mechanical characteristics of polycarbonate on the example of polycarbonate samples for 3D printing, to obtain the dependence of stress intensity on strain intensity taking into account compressibility. An experimental study of the mechanical properties of polycarbonate used in 3D printing has been carried out. Polycarbonate samples were made to perform tensile tests on a 3D printer. A series of stretching experiments were carried out in the elastic stage of samples to determine the Poisson's ratio of polycarbonate. To calculate the tensile strength, the conditional yield strength, polycarbonate samples were tested for rupture. Diagrams of conditional stresses from relative deformations are constructed. Since polycarbonate for 3D printing mainly works in the elasticity stage, the study constructed diagrams of polycarbonate deformation taking into account the compressibility of the material. According to the results of the study, the average values of the tensile elastic limit, the conditional yield strength, the tensile strength and the relative deformation at rupture of samples made by the 3d- printing method of polycarbonate were obtained. Deformations curves will allow us to estimate the stress-strain state of loaded polycarbonate elements not only under simple tension, but also under conditions of complex volumetric loading, since they relate the intensity of stresses and deformations.