Summary
If you make $4,000 a year living in the region of Colorado, USA, you will be taxed $306. That means that your net pay will be $3,694 per year, or $308 per month. Your average tax rate is 7.7% and your marginal tax rate is 12.3%. 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 $12.25, hence, your net pay will only increase by $87.75.
Bonus Example
A $1,000 bonus will generate an extra $878 of net incomes. A $5,000 bonus will generate an extra $4,388 of net incomes.