Summary
If you make $18,281 a year living in the region of California, USA, you will be taxed $2,327. That means that your net pay will be $15,954 per year, or $1,330 per month. Your average tax rate is 12.7% and your marginal tax rate is 21.0%. 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 $20.95, hence, your net pay will only increase by $79.05.
Bonus Example
A $1,000 bonus will generate an extra $791 of net incomes. A $5,000 bonus will generate an extra $3,953 of net incomes.