Disclosed is a method for determining an operating flow rate for a chromatographic column (4) in an HPLC system (1). The method comprises: measuring/calculating a pressure of the system (1) without the chromatographic column (4) for one or more flow rates; fitting a function to the flow rate(s) and corresponding pressure(s), calculating from the function and a predetermined recommended flow rate for the chromatographic column (4) a system pressure drop at the predetermined recommended flow rate. An operating flow rate is determined by summing the system pressure drop and a maximal column pressure limit, and determining a contribution of the system pressure drop to the summed pressure. If this contribution exceeds 1% an operating flow rate for the column is determined to a flow rate that corresponds to a pressure at a pressure monitor arranged before the column that is lower than the predetermined maximum column pressure limit.