Surname กรรณรัตน์ (Kannarat 
, Karunaratna 
, กรรณรัตน์ ) , all over the world, is quite a rare last name. The cognomen กรรณรัตน์ is characteristic of Sri Lanka, where it is quite a common surname, Australia, where it is a rare surname, and Japan. Measured by absolute frequency, the name is most common in Sri Lanka, Japan, and Thailand. Very seldom, กรรณรัตน์ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Kannarat | United States, India, Thailand |
| Karunaratna | Japan, Australia, Sri Lanka, United Arab Emirates, Indonesia |
| กรรณรัตน์ | Thailand |
Karnrat, Karunaratne, and Knanarat