Generalized Kelvin–Voigt and Maxwell models using Prony series are some of the most well-known models to characterize the behavior of polymers. The simulation software for viscoelastic materials generally implement only some material models. Therefore, for the practice of the engineer, it is very useful to have formulas that establish the equivalence between different models. Although the existence of these relationships is a well-established fact, moving from one model to another involves a relatively long process. This article presents a development of the relationships between generalized Kelvin–Voigt and Maxwell models using the aforementioned series and their respective relaxation and creep coefficients for one and two summations. The relationship between the singular points (maximums, minimums and inflexion points) is also included.