A caliper includes two legs pivotably connected together at first ends thereof. Second ends of the legs can abut opposite first and second sides of an object to be gauged. Each leg includes first and second faces extending between the first and second ends. A scale is formed on the first surface of each leg. Each leg further includes an inclined surface between the first and second faces. The size of the object is indicated by an intersection of the scales. The inclined surfaces of the legs abut third and fourth faces of the object so that the gauging result is reliable.