Abstract We analyzed the effect of the curvature of the path on the energy spectrum of an electron confined in a closed nanoscopic loop in the presence of magnetic and electric external fields has been studied. The system was modeled using the stationary Schrödinger equation in the framework of the approximation of effective mass and enveloping function, which was solved using the finite element method. The closed loop has been modeled theoretically as a flat waveguide, whose width is small compared to the length of the path. These geometries allowed putting in evidence the variation in the confinement potential of the electron due to changes in the curvature. The variation of the electronic spectrum and the electronic densities for some low-lying energy states were analyzed as a function of the intensity of a magnetic field applied in the direction of growth and an electric field applied in the structural plane. The results demonstrate, with clarity, the high sensitivity of the electronic spectrum of a closed nanoscopic loop in the presence of changes in the curvature of the path, which translates into high sensitivity in electronic, magnetic and optical properties.