If you make 300,000,- kr a year living in the region of Lolland, Denmark, you will be taxed 106,954, kr. That means that your net pay will be 193,046,- kr per year, or 16,087,- kr per month. Your average tax rate is 35.7% and your marginal tax rate is 42.2%. 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 42.15,- kr, hence, your net pay will only increase by 57.85,- kr.
A 1,000,- kr bonus will generate an extra 579,- kr of net incomes. A 5,000,- kr bonus will generate an extra 2,893,- kr of net incomes.