Many astrophysical problems in the theory of formation and evolution of stars and stellar groups require knowledge of the mass or age of individual stars. Stellar masses and ages are not directly observable parameters, and most of the methods used to determine them are based on the calibrating relations obtained from observations or from theoretical considerations. In most cases, the mass-luminosity relation, based on the masses of approximately two hundred well-studied binaries, is the only way to estimate the mass of single stars. Unfortunately, the statistical nature of the mass-luminosity relation means that the stellar masses determined with it may only be considered as approximate. The establishment of methods for estimating stellar masses and ages of stars with accuracy comparable to direct methods remains a challenging task. This work proposes a way to use the location of a star in the HR diagram to estimate its mass and age based on modern stellar models. The method is based on the geometric similarity of evolutionary tracks for the stars at the same evolutionary stage. To examine the proposed approach and involved assumptions, it has been applied to various test data sets.