Family name แก้วคูณ (Kaewkoon 
, แก้วคูณ, Kaewkhoon ) , around the world, is a rare surname. The family name แก้วคูณ is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname, and Malaysia, where it is an extremely rare surname. Very seldom, แก้วคูณ is the forename as well as the last name.