Cognomen Удай (Uday 
, Udai 
, Удай 
) , in the entire world, is a common last name. The surname Удай is characteristic of Israel, where it is quite a rare surname, Nepal, and Qatar. Not in comparison with a country's population, the name is most common in India, Japan, and Bangladesh. Much more prevalently, Удай is the forename as well as the last name.