A method for determining an operating flow rate for a chromatographic column in a high performance liquid chromatographic system, the system comprising: a liquid reservoir for a liquid medium, a chromatographic column in fluid communication with the liquid reservoir, said chromatographic column having a predetermined recommended flow rate and a predetermined maximal column pressure limit, a system pump arrangeable to force liquid from the liquid reservoir through the chromatographic column at a certain flow rate, a system controller; a fluid flow path connecting the liquid reservoir, the system pump and the chromatographic column, and a pressure monitor arranged before said chromatographic column, the method being performable by the system controller and comprising the steps of: a) measuring using the pressure monitor, or calculating (101b, 101c) a pressure of the system without the chromatographic column using the system controller, for one or more flow rates, b) fitting a function to said flow rate(s) and corresponding measured or calculated pressure(s), c) calculating from said function and said predetermined recommended flow rate for the chromatographic column a system pressure drop at said predetermined recommended flow rate, and d) determining an operating flow rate for the chromatographic column by summing the system pressure drop and the predetermined maximal column pressure limit, and determining a contribution of the system pressure drop to the summed pressure, wherein if this contribution exceeds 1% an operating flow rate for the chromatographic column is determined to a flow rate that corresponds to a pressure at the pressure monitor that is lower than the predetermined maximum column pressure limit. a liquid reservoir for a liquid medium, a chromatographic column in fluid communication with the liquid reservoir, said chromatographic column having a predetermined recommended flow rate and a predetermined maximal column pressure limit, a system pump arrangeable to force liquid from the liquid reservoir through the chromatographic column at a certain flow rate, a system controller; a fluid flow path connecting the liquid reservoir, the system pump and the chromatographic column, and a pressure monitor arranged before said chromatographic column, the method being performable by the system controller and comprising the steps of: a) measuring using the pressure monitor, or calculating (101b, 101c) a pressure of the system without the chromatographic column using the system controller, for one or more flow rates, b) fitting a function to said flow rate(s) and corresponding measured or calculated pressure(s), c) calculating from said function and said predetermined recommended flow rate for the chromatographic column a system pressure drop at said predetermined recommended flow rate, and d) determining an operating flow rate for the chromatographic column by summing the system pressure drop and the predetermined maximal column pressure limit, and determining a contribution of the system pressure drop to the summed pressure, wherein if this contribution exceeds 1% an operating flow rate for the chromatographic column is determined to a flow rate that corresponds to a pressure at the pressure monitor that is lower than the predetermined maximum column pressure limit. a) measuring using the pressure monitor, or calculating (101b, 101c) a pressure of the system without the chromatographic column using the system controller, for one or more flow rates, b) fitting a function to said flow rate(s) and corresponding measured or calculated pressure(s), c) calculating from said function and said predetermined recommended flow rate for the chromatographic column a system pressure drop at said predetermined recommended flow rate, and d) determining an operating flow rate for the chromatographic column by summing the system pressure drop and the predetermined maximal column pressure limit, and determining a contribution of the system pressure drop to the summed pressure, wherein if this contribution exceeds 1% an operating flow rate for the chromatographic column is determined to a flow rate that corresponds to a pressure at the pressure monitor that is lower than the predetermined maximum column pressure limit.