Summary
If you make 399,999,995 ₫ a year living in Vietnam, you will be taxed 93,799,999 ₫. That means that your net pay will be 306,199,996 ₫ per year, or 25,516,666 ₫ per month. Your average tax rate is 23.5% and your marginal tax rate is 30.3%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of 100 ₫ in your salary will be taxed 30.29 ₫, hence, your net pay will only increase by 69.71 ₫.
Bonus Example
A 1,000 ₫ bonus will generate an extra 697 ₫ of net incomes. A 5,000 ₫ bonus will generate an extra 3,486 ₫ of net incomes.