A method for determining the reference focus position of a laser beam

A method for determining the reference focus position (15) of a laser beam (2) of a laser installation (1) comprising the steps of: a. Generating at least two incisions (21, 22) with the laser beam (2) of the laser unit (1) in a plate-like body (20), wherein for the at least two incisions (21, 22) are set different focal positions; b. Irradiating the plate-like body (20) with the laser beam (2); c. Detecting edges of the incisions (21, 22) by sensing one or more properties related to the irradiation of the plate-like body parameters (30); d. Determining the width (b) of the incisions (21, 22) based on the or the detected parameters (30).