Cognomen Kalnoi (Кальной 
, Kalnoi 
) , around the globe, is a rare family name. The last name Kalnoi is habitual in Kazakhstan, where it is a rare surname, Ukraine, and Russia. Much less frequently, Kalnoi is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Кальной | Kazakhstan, Russia, Ukraine, Belarus |
| Kalnoi | Germany, Russia |