Summary
If you make 21,000 kr a year living in the region of Frederiksberg, Denmark, you will be taxed 6,828 kr. That means that your net pay will be 14,172 kr per year, or 1,181 kr per month. Your average tax rate is 32.5% and your marginal tax rate is 30.1%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of 100 kr in your salary will be taxed 30.07 kr, hence, your net pay will only increase by 69.93 kr.
Bonus Example
A 1,000 kr bonus will generate an extra 699 kr of net incomes. A 5,000 kr bonus will generate an extra 3,497 kr of net incomes.