If you make 2,000,000 Kč a year living in Czech Republic, you will be taxed 485,163 Kč. That means that your net pay will be 1,514,837 Kč per year, or 126,236 Kč per month. Your average tax rate is 24.3% and your marginal tax rate is 23.1%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of 100 Kč in your salary will be taxed 23.14 Kč, hence, your net pay will only increase by 76.86 Kč.
A 1,000 Kč bonus will generate an extra 769 Kč of net incomes. A 5,000 Kč bonus will generate an extra 3,843 Kč of net incomes.