Summary
If you make 270,000,640 원 a year living in South Korea, you will be taxed 93,160,899 원. That means that your net pay will be 176,839,741 원 per year, or 14,736,645 원 per month. Your average tax rate is 34.5% and your marginal tax rate is 43.8%. 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 43.77 원, hence, your net pay will only increase by 56.23 원.
Bonus Example
A 1,000 원 bonus will generate an extra 562 원 of net incomes. A 5,000 원 bonus will generate an extra 2,812 원 of net incomes.