Abstract: Weighing apparatus for determining the tare and net weights of a container containing a liquid or a substance behaving like a liquid without requiring separate weighing of the empty container or its contents including apparatus for applying force to the container whereby force interactions between the liquid and the container are negligible for at least a predetermined measuring duration; and apparatus for sensing characteristics of the force applied to the container and of the motion of the container at the measuring duration for determining the tare weight of the container.