A paving screed to be employed on a road finisher comprises a base screed, the operating width of which may be modified by protractable extending units and/or separate removable bolt-on extensions. The paving screed also includes a plurality of side plates, each being mountable on an outer end of the base screed or an extending unit or a bolt-on extension and which delimit the operating width. At least one reference element for determining the operating width is provided on one of the side plates, and that the at least one reference element is detectable by one or more sensor units when the side plates are each mounted on the outer ends of the base screed, an extending unit or a bolt-on extension.