The article proposes a method to calculate eigenstates and eigenfunctions of the conduction band in V-groove quantum wires, which is based on conformal mapping and Fourier expansion. Consequently, the method relies essentially on an analytical calculation with input data as measured with V-groove quantum wires. The method allows one to take into account the hermiticity of the Schrödinger equation as well as the nonparabolicity of the effective mass. We analyze the influence of both effects on the calculated results, showing that an error of up to 30% is incurred if both effects are neglected.