Summary
If you make 39,959,920 ₫ a year living in Vietnam, you will be taxed 5,983,998 ₫. That means that your net pay will be 33,975,922 ₫ per year, or 2,831,327 ₫ per month. Your average tax rate is 15.0% and your marginal tax rate is 15.0%. 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 14.98 ₫, hence, your net pay will only increase by 85.02 ₫.
Bonus Example
A 1,000 ₫ bonus will generate an extra 850 ₫ of net incomes. A 5,000 ₫ bonus will generate an extra 4,251 ₫ of net incomes.