A single subband model for InAs/GaAs quantum dots (QDs) and quantum rings (QRs), where the energy dependence of the electron effective mass is defined by the Kane formula, is used. Model assumptions lead to the nonlinear Schrodinger equation in a three-dimensional space. Geometrical parameters of the model are based on the fabrication of QRs from a QD procedure for which the experimental capacitance-gate voltage (CV) data are available. The confinement state energies of QDs (QRs) are calculated. Obtained results for single electron energy levels reveal a good agreement with the CV spectroscopy experiments. (c) 2006 American Vacuum Society.