Summary
If you make $3,931 a year living in the region of Colorado, USA, you will be taxed $301. That means that your net pay will be $3,630 per year, or $303 per month. Your average tax rate is 7.7% and your marginal tax rate is 9.1%. 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 $9.08, hence, your net pay will only increase by $90.92.
Bonus Example
A $1,000 bonus will generate an extra $909 of net incomes. A $5,000 bonus will generate an extra $4,546 of net incomes.