A calibration procedure for content depth profile analysis by glow discharge optical emission spectroscopy is presented. This new method is based on the well established relative or internal standard method. The method allows reduction of the number of CRM with known sputtering rates to a strict minimum, while still using a large number of CRMs for establishing the analytical curves. The new calibration method allows the uncertainty in the calculation of the chemical composition to be separated from the uncertainties of sputtering rate measurements. The application of this new calibration procedure is applied to industrial samples and further possible improvements are discussed.