External forces acting inward from the surface of the material are called compression forces and create pressure stresses. It is considered the reverse of the tensile test. The strength values of brittle materials are generally determined by the compression test. It is especially used for determining the strength of brick, concrete and similar materials.

In the compression test, cylindrical or cube shaped samples are placed between two parallel tables and the deformations caused by the applied force are measured with the help of an extensometer.