A packaging machine and a method for controlling the position of a lower and/or upper material web on a packaging machine. A lower material web is unwound from a supply roll and transported intermittently or continuously along the packaging machine. Packaging recesses are optionally formed in the lower material web in a forming station, and the lower material web, preferably the packaging recesses, are then filled with products to be packaged. An upper material web is then sealed to the lower material web in a sealing station, the lower and upper material web each being unwound from a supply roll.