Family name Kulchak (Kulchak 
, Кульчак 
) , all around the world, is a rare surname. The surname Kulchak is characteristic of Ukraine, where it is a rare surname, Portugal, where it is a very rare surname, and Kazakhstan. Measured by absolute frequency, it is the most numerous in Ukraine, Russia, and the United States.
| VARIANT | COUNTRY |
|---|---|
| Kulchak | Ukraine, Portugal, United States, Russia |
| Кульчак | Russia, Ukraine, Kazakhstan |