The United States has several different sets of tax laws. Federal tax law applies to taxes paid to the United States government. State tax laws apply to taxes paid to the state in which you work and/or live. In some places there may also be local or city taxes. It is important to comply with all federal, state, and local tax laws that apply to you.
The federal and state tax system is based on a graduated tax system, which means that the percentage of tax a person pays is dependent on the amount of income they earn and the number of dependents they have (nonresident aliens can only claim one dependent, unless they are a resident of Canada, Mexico, South Korea or student from India). If you earn a smaller income, you pay a smaller percentage in tax, but if you earn a larger salary, you pay a higher percentage. The local or city taxes (work location) are not on a graduated tax system. Most local taxes are withheld based on a fixed percentage. For example, Columbus taxes are a fixed 2.5 percent.