A system for remotely indicating the level of grain being loaded into a grain trailer. Plural vertically oriented sensing strips are affixed to a trailer's hopper(s) sidewall of the trailer's hopper(s) at spaced locations. Signals from transducer elements on the strips are delivered to an electronics module on the trailer's forward wall. The electronics module includes a multiplexer for sampling the state of the strip transducers and a wireless transmitter for relaying the state data to a receiver and microprocessor in the cab of a towing vehicle. The microprocessor presents a visual display of height reached by the grain in a hopper as loading continues. Following system calibration where a pixel count of the load being displayed and a measured net weight of the load are determined using a scale, a calibration factor corresponding to the weight-per-pixel is stored for use in computing the weight and volume of subsequent loads.