Summary
If you make $504,156,648 a year living in New Zealand, you will be taxed $196,603,206. That means that your net pay will be $307,553,442 per year, or $25,629,454 per month. Your average tax rate is 39.0% and your marginal tax rate is 39.0%. This marginal tax rate means that your immediate additional income will be taxed at this rate. For instance, an increase of $100 in your salary will be taxed $39, hence, your net pay will only increase by $61.
Bonus Example
A $1,000 bonus will generate an extra $610 of net incomes. A $5,000 bonus will generate an extra $3,050 of net incomes.