In this study, the theoretical principles necessary to determine the exact magnitude of a moving electron, depending on the speed of movement, will be exposed. The equations are specifically discussed to determine the radius R of the moving electron, which refers to the electron movement velocity v and the resting mass m0. The mechanical moment of inertia of a sphere around one of its diameters is determined by the relationship between the total kinetic energy of a moving electron as the sum of the two components (translatable and rotating). Using the theory of Louis de Broglie, which shows impulse preservation, the wavelength (associated with the particle) was calculated. The wave frequency (associated with the moving electron) was determined and the moving electron kinetic energy was estimated by decreasing the total resting energy of the electron from the total energy of the moving electrons.