Abstract: A caliper device for taking the dimension of an object such as livestock having caliper arms with hand members for gripping the rib cage of an animal and telescoping first and second members assembled for manual relative longitudinal movement when taking the dimension of the rib cage. The first member abutting the back of the animal and carrying the caliper arms and the second member carrying a cursor and weight graduations indicating an appropriate weight graduation, estimated according to the size of the rib cage when gripped by caliper arms and hand members. Other embodiments include the first member carrying a series of lights each marking a respective weight graduation or carrying a clock-like gauge system for indicating the estimated weight of an animal.