A filling degree gauge for measuring and displaying a residual filling potential of a target area, such as a container, being filled through a target, such as an open top, with goods by a goods carrier, such as a discharge spout, of an agricultural vehicle, such as a harvester, has a 3D sensor for observing at least a part of the target area including at least a part of the target, a data control system and a visual display unit. The data control system operates to provide on the visual display unit a visual display indicating residual filling potential by indicating the current one of at least three different levels of residual filling potential.