A method for altering the width of a strip-shaped rolled material (5), before, during or after hot rolling the rolled material in a hot rolling mill. The problem is to specify a method for altering width so that the length of a rolled out transition piece lying outside width tolerances can be reduced. Scrap losses are to be reduced. The crown of at least one working roll and/or at least one backing roll of a stand (7) is set as a function of a width error e=B−B between a setpoint width Bsetp and the width B of the rolled material (5), wherein the crown is increased when e>0 and the crown is reduced when e