Container volume measuring device and method

The volume measuring device has a reservoir of known volume attached to a measuring tube. The measuring tube is also attached to a container mount configured to sealably engage a container. Liquid partially fills the measuring tube and the volume of liquid contained therein can be measured by measuring its height. The measuring tube pivots between two measuring orientations. In the first measuring orientation, the volume of liquid in the measuring tube equals the total volume of liquid minus the volume of the reservoir. In the second measuring orientation, the volume of liquid in the measuring tube equals the total volume minus the volume of the container. Thus, the difference in the volume of liquid contained in the measuring tube in the two orientations equals the difference between the known volume of the reservoir and the unknown volume of the container, and the volume of the container can be calculated.