If you make NT$ 7,000,000 a year living in Taiwan, you will be taxed NT$ 2,082,267. That means that your net pay will be NT$ 4,917,733 per year, or NT$ 409,811 per month. Your average tax rate is 29.8% and your marginal tax rate is 59.4%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of NT$ 100 in your salary will be taxed NT$ 59.37, hence, your net pay will only increase by NT$ 40.63.
A NT$ 1,000 bonus will generate an extra NT$ 406 of net incomes. A NT$ 5,000 bonus will generate an extra NT$ 2,032 of net incomes.