Grounding grid performance can be measured in terms of grounding resistance, but it is preferable to include the distribution of surface potential and, subsequently, the touch and step voltages over the area above the substation ground grid and beyond. Two methods are used in this paper to compute the grounding resistance (Rg) and the earth surface potential (ESP) due to discharging current into grounding grids. The first one is the charge (current) simulation method (CSM) and the other is the boundary element method (BEM). For BEM, commercial software TOTBEM by university of La Cournia, Spain is used for computing ESP and Rg. The owned FORTRAN code is provided to calculate the ESP and Rg. The soil is assumed to multilayer soil. The paper focuses the comparison between these two methods for calculating ESP and Rg. In case of grounding resistance, a comparison between the two methods results and IEEE Standard formula is presented.