National Health Insurance
If you make 140,000 원 a year living in South Korea, you will be taxed 14,964 원. That means that your net pay will be 125,036 원 per year, or 10,420 원 per month. Your average tax rate is 10.7% and your marginal tax rate is 10.7%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of 100 원 in your salary will be taxed 10.69 원, hence, your net pay will only increase by 89.31 원.
A 1,000 원 bonus will generate an extra 893 원 of net incomes. A 5,000 원 bonus will generate an extra 4,466 원 of net incomes.
NOTE* Withholding is calculated based on the tables of South Korea, income tax. For simplification purposes some variables (such as marital status and others) have been assumed. This document does not represent legal authority and shall be used for approximation purposes only.