The swift cup test is used die, flat bottom cylindrical punch, circular blank with diameter and thickness and blank holder. In this test the circular blank with different diameters with constant thickness placed on die surface and drawn into cylindrical cup until fracture is occurred at the bottom of cup by using flat bottom cylindrical punch. The diameter of blank for successful formation of cup is measured. This is the diameter of blank; above this diameter fracture is occurred in the cup and before this diameter no fracture is obtained in the cup. This diameter is called maximum diameter of blank. It is also called critical diameter of blank. It is used to measure the formability index. It is expressed in limiting drawing ratio. It gives formability of sheet metals.