Surname Krupiak (Krupiak 
, Крупяк 
) , across the world, is a rare family name. The family name Krupiak is habitual in Ukraine, where it is a rare surname, Poland, and France, where it is a very rare surname. Not in comparison with a country's population, it is commonest in Ukraine, Poland, and the United States. Likewise, Krupiak is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Krupiak | Germany, France, Poland, United Kingdom, United States |
| Крупяк | Russia, Ukraine |