Last name หวานใจ (Wanchai 
, หวานใจ , Sweetheart 
) , worldwide, is quite a rare family name. The cognomen หวานใจ is habitual in Thailand, where it is quite a rare surname, Ghana, where it is a rare surname, and Myanmar. More frequently, หวานใจ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Wanchai | Thailand, China, Myanmar, India, United States |
| Whanjai, หวานใจ | Thailand |
| Sweetheart | Philippines, Thailand, China, India, Ghana |
Swangjai, Sweetalice, and Waanw