Cognomen Будаи (Budai 
, Buday 
, Boudai 
) , globally, is a common last name. The last name Будаи is characteristic of Eastern Europe, particularly Hungary, where it is a common surname, Slovakia, where it is quite a common surname, and Romania. Not in comparison with a country's population, this name is the most popular in Hungary, Romania, and Philippines. Also, Будаи is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Budai | Japan, Romania, Philippines, Hungary, India |
| Buday | Romania, Philippines, Hungary, India, Slovakia |
| Boudai | Algeria, Kuwait, United States, India, France |
| Будаи | Russia |