**Ultimate tensile strength (UTS)**, often shortened to **tensile strength (TS)**, **ultimate strength**, or **Ftu** within equations, is the capacity of a material or structure to withstand loads tending to elongate, as opposed to compressive strength, which withstands loads tending to reduce size. In other words, tensile strength resists tension (being pulled apart), whereas compressive strength resists compression (being pushed together).

The maximum stress measures ultimate tensile strength that a material can withstand while being stretched or pulled before breaking. In the study of the strength of materials, tensile strength, compressive strength, and shear strength can be analyzed independently. Some materials break very sharply, without plastic deformation, in what is called a brittle failure. Other materials, which are more ductile, including most metals, experience some plastic deformation and possibly necking before fracture.