Summary
If you make $3,989,998 a year living in Australia, you will be taxed $1,845,966. That means that your net pay will be $2,144,032 per year, or $178,669 per month. Your average tax rate is 46.3% and your marginal tax rate is 47.0%. 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 $47, hence, your net pay will only increase by $53.
Bonus Example
A $1,000 bonus will generate an extra $530 of net incomes. A $5,000 bonus will generate an extra $2,650 of net incomes.