A method of producing helical springs by spring winding with a numerically controlled spring winding machine includes feeding a wire, controlled by an NC control program, through a feed device to a forming device of the spring winding machine, forming a helical spring from the wire with the forming device, measuring an actual geometry of the helical spring to obtain actual spring data, comparing the actual spring data with nominal spring data to determine discrepancy data which represents a discrepancy between an actual geometry and a predetermined nominal geometry of the helical spring for at least one spring geometry parameter, analyzing the discrepancy data and producing correction data when discrepancies are outside selected predetermined tolerance limits, varying an actuating movement of at least a portion of the forming device on the basis of the correction data for producing a next helical spring, selecting a spring section, determining a correction value for an actuating movement of a portion of the forming device, which correction value influences a spring geometry parameter in the selected spring section, and correcting the NC control program based on the correction value.