The numerical inversion of the Laplace transform (NILT) is widely used in several engineer applications particularly in Electromagnetic Transients (EMT). Many works that use NILT were motivated by finding an easy, fast and accurate way to solve differential equations, in order to obtain a numerical solution. Based on the comparison between analytical results and NILT algorithms results, the effectiveness and reliability of numerical inverse was demonstrated. This paper presents a detailed description and analysis, of four different ways to perform the NILT based on Fast Fourier Transform (FFT) algorithm and its applications in EMT simulations.