Surname คัย (Khai 
, คัย 
, Kayyy 
) , globally, is a common cognomen. The cognomen คัย is habitual in South-eastern Asia, particularly Malaysia, where it is quite a common surname, Myanmar, and Brunei (explore the name in all countries). Measured by absolute frequency, it most frequently occurs in South-eastern Asia, particularly Malaysia, Myanmar, and Vietnam. Also, คัย is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Khai | Myanmar, Vietnam, India, Mongolia, Malaysia |
| คัย | Thailand |
| Kayyy | United States |