If you make 300,000 kr a year living in the region of Frederiksberg, Denmark, you will be taxed 90,115 kr. That means that your net pay will be 209,885 kr per year, or 17,490 kr per month. Your average tax rate is 30.0% 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 30.08 kr, hence, your net pay will only increase by 69.92 kr.
A 1,000 kr bonus will generate an extra 699 kr of net incomes. A 5,000 kr bonus will generate an extra 3,496 kr of net incomes.