The cylinder test is the test most commonly used for determining concrete strength in the USA and continental Europe. A 300mm (12 in.) high by 150mm (6 in.) wide cylinder of concrete is cast, is cured for the appropriate time (see Concrete Age at Testing), and is then compressed between the two parallel faces. The stress at failure is taken to be the compressive strength of the concrete.
Generally the cylinder test gives lower compressive strengths than the alternative cube test. See Conversion between Cube and Cylinder Strengths.