Surname คำคูณ (Khamkoon 
, Kamkoon , Khamkhun 
) , in all the world, is a rare cognomen. The cognomen คำคูณ is habitual in Thailand, where it is a rare surname, Singapore, and the United States, where it is an extremely rare surname. Likewise, คำคูณ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Khamkoon | Laos, Thailand, United States |
| Kamkoon | Thailand |
| Khamkhun | Thailand, Singapore |