Summary
If you make $12,960 a year living in the region of Montana, USA, you will be taxed $1,384. That means that your net pay will be $11,576 per year, or $965 per month. Your average tax rate is 10.7% and your marginal tax rate is 18.3%. 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 $18.25, hence, your net pay will only increase by $81.75.
Bonus Example
A $1,000 bonus will generate an extra $818 of net incomes. A $5,000 bonus will generate an extra $4,088 of net incomes.