Cognomen 恺欣 (Kai Xin 
, 恺欣 ) , all over the world, is a rare last name. The family name 恺欣 is habitual in Singapore, where it is quite a rare surname, Malaysia, where it is a rare surname, and China, where it is an extremely rare surname. More frequently, 恺欣 is the forename as well as the last name.