A signal that reaches beyond the viewing area of a display screen. A slight overscan is generally not noticeable on a TV set, but is apparent on a computer monitor where taskbars are typically at the extreme ends of the viewing area.

Some HDTVs have a slight overscan of approximately 4-6%, and signals sent from a PC to an HDTV set may also overscan if not adjusted correctly. When the zoom mode in an HDTV set is selected to fill the sides of the wide screen, it creates the effect of an extreme overscan, although intentional. Contrast with underscan. See HDTV display modes.