The main objective of this paper is to present an approximate numerical solution of the Klein-Gordon equation. For this purpose, the basic concepts associated with the numerical method used to obtain the approximate solution will be presented initially. In our case, we considered as a hypothesis the fact that using the finite element method and in particular the Galerkin method, it is possible to perform a superb numerical approximation of the solution of the Klein-Gordon equation. For this purpose, we will present some of the solutions that have been obtained by employing the modified Adomian decomposition method, via a transformation and Exp-function method and comparison with Adomian's, and using the variational method. This will allow better understanding of the effectiveness of the finite element method because the solutions will be represented in space and time. The novelty results from the fact of being able to take the solutions known as initial and boundary conditions and observe that effectively at great lengths the solution stabilizes at zero and that over time the approximate solutions stabilize. Finally, the simulations obtained by the finite element method indicate that the Klein-Gordon equation is damped nonlinear, its solution stabilizes at and and for short times, the function remains close to zero. Keywords: approximate solution, finite element method, nonlinear equation, the Klein-Gordon equation, the Galerkin solution. https://doi.org/10.55463/issn.1674-2974.50.7.23