Although the Tax Rate in Korea is estimated to be 3.3%, there is no exact rate for income tax; it depends on your salary. For example, a salary of 2 million won is about 1.4x% (28,950Won). If you pay 3.3% tax rate and you are giving 66,000 won to your boss, wake up! You should be paying less.
If you need advice on getting back the money you have lost in tax, you can file a complaint (http://www.nts.go.kr/front/eng/faqs_qna/qna_list.asp). You can also visit the site for Tax Rate in Korea (http://www.nta.go.kr/eng/default.html) or dial the English hot line number: 02-397-1440.
To know more about employment permit system and employment of migrant workers, you can contact Foreign Worforce policy division.
The booklet “Income Tax Guide for Foreigners” has details on how to fill out tax forms and file returns online (http://www.nta.go.kr/eng/default.html).