The knowledge of equilibrium constants is essential for the best adjustment of analytical methods. Among the various methods for its calculation and refinement, the potentiometric and spectrophotometric methods stand out, although they are not always applicable, as electrochemical or thermometric methods are available as an alternative. In this paper, a description of different methods to obtain and refine protonation equilibrium constants from differential-pulse amperometric titration data is made. The calculation and refinement programs were applied for the determination of the overlapping values of equilibrium constants of maleinimidodioxime (MIDO), where the deprotonation constants and molar currents are treated as unknown parameters. For this purpose, the program EquilAMP, which is based on the least-squares principle and which is capable of simultaneous refinement of up four parameters, was developed.