Percent elongation quantifies the ability of an element or compound to stretch up to its breaking point. It is measured by dividing the change in length (up to the breaking point) by the original length, then multiplying by 100. Materials with a higher percentage elongation can stretch more before breaking.
Elongation is a form of physical deformation, or a change in the physical shape or orientation of a material. Brittle materials, such as glass or ceramics, have low elongation while very ductile materials, such as rubber of some plastics, have very high elongation. Metals tend to have low to moderate elongation capabilities.