Here is the link for the Korean class level test:

https://nuri.iksi.or.kr/front/page/participation/onlineLevelTest/main.do

This is provided by King Sejong Institute, and before you take the test, you should sign up first. 

There are two types of tests: beginner and intermediate. So select one depending on your Korean level. 

Note that once you take a test, you can't take the same level test again for three months. 

However, you can take a different level test. 

Below is the recommended class according to test results.