Cognomen Guelfgat (Guelfgat 
, Гельфгат 
) , in the entire world, is a rare last name. The cognomen Guelfgat is characteristic of Russia, where it is a rare surname, Ukraine, where it is a very rare surname, and Kazakhstan. In absolute terms, it is the most numerous in Russia, Ukraine, and Germany.
| VARIANT | COUNTRY |
|---|---|
| Guelfgat | Germany, Canada |
| Гельфгат | Kazakhstan, Russia, Ukraine |