A method for determining the outlet cross-section of a component including one or more turbine blades, in particular of a turbine blade twin, of a gas turbine, in which at least one closed outlet cross-section is measured between the turbine blades, and/or respective open outlet cross-sections are measured on the side of the at least one turbine blade, using a measurement device, wherein in order to determine the corresponding outlet cross-section its respective bounding walls are traversed by the measurement device along a measurement line.