Summary
If you make 171,600,000 원 a year living in South Korea, you will be taxed 50,283,871 원. That means that your net pay will be 121,316,129 원 per year, or 10,109,677 원 per month. Your average tax rate is 29.3% and your marginal tax rate is 41.5%. 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 41.54 원, hence, your net pay will only increase by 58.46 원.
Bonus Example
A 1,000 원 bonus will generate an extra 585 원 of net incomes. A 5,000 원 bonus will generate an extra 2,923 원 of net incomes.