Summary
If you make $66,661 a year living in the region of Illinois, USA, you will be taxed $15,833. That means that your net pay will be $50,828 per year, or $4,236 per month. Your average tax rate is 23.8% and your marginal tax rate is 34.6%. 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 $34.60, hence, your net pay will only increase by $65.40.
Bonus Example
A $1,000 bonus will generate an extra $654 of net incomes. A $5,000 bonus will generate an extra $3,270 of net incomes.