Cognomen Калю (Калю 
, Kalju 
, Kalyu 
) , around the globe, is a rare last name. The surname Калю is characteristic of Estonia, where it is quite a rare surname, Bulgaria, and Norway, where it is a rare surname. Measured by absolute frequency, it most frequently occurs in Bulgaria, Estonia, and Ethiopia. Also, Калю is the forename as well as the last name.