Summary
If you make $3,963 a year living in the region of Iowa, USA, you will be taxed $309. That means that your net pay will be $3,654 per year, or $304 per month. Your average tax rate is 7.8% and your marginal tax rate is 8.2%. 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 $8.20, hence, your net pay will only increase by $91.80.
Bonus Example
A $1,000 bonus will generate an extra $918 of net incomes. A $5,000 bonus will generate an extra $4,590 of net incomes.