Surname คูณสิน (คูณสิน 
, Koon Sin 
, Koonsin ) , around the globe, is a very rare family name. The surname คูณสิน is habitual in South-eastern Asia, particularly Singapore, where it is a rare surname, Thailand, where it is a very rare surname, and Malaysia, where it is an extremely rare surname. Also, คูณสิน is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| คูณสิน, Koonsin | Thailand |
| Koon Sin | Malaysia, Singapore |