This paper deals with the calculation of electric field in a copper piece of cubic shape which is submitted to a sinusoidal magnetic field. This 3D problem is set into equation and solved by means of two different approaches. A stochastic method for 3-D electric field computations is presented and compared to a finite element method. The main goal of this paper is to compare these two methods on a classical problem putting forward the advantages of the chosen method. First of all, we present the problem modelling. Then, the Monte-Carlo method used to solve 3D time dependent problem is described and is compared to the finite element method, in the last part.