A robust, simple and fast procedure for the calculation of uncertainties in static relative permittivity (εs) computed via molecular dynamics (MD) is proposed. It arises as a direct application of well founded statistical methods for auto-correlated variables. Also, in order to deal with the lack of experimental data on εs and relaxation times at different temperatures, a method for their prediction is suggested. This method requires one experimental value and at least two MD simulations. In the case of relaxation times, a theoretical justification is provided.