Income tax in the United States increase complexity, irrespective of the system's flatness or lack thereof. Income tax is also levied by most U.S. states and many localities on individuals, corporations, estates, and trusts. These taxes are in addition to federal income tax and are deductible for federal tax purposes. State and local income tax rates vary from 1% to 16% of taxable income. Some state and local income tax rates are flat (single rate) and some are graduated. State and local definitions of what income is taxable vary highly. Some states incorporate the federal definitions by reference. Taxable income is defined separately and differently for
Income tax in the United States of certain types of business expenses. Individuals are also allowed credits related to education expenses, retirement savings, child care expenses, some health care premiums, and a credit for each child. Each of the credits is subject to specific rules and limitations. Some credits are treated as refundable payments. Alternative Minimum Tax: All taxpayers are also subject to the Alternative Minimum Tax if their income exceeds certain exclusion amounts. This tax applies only if it exceeds regular income tax, and is reduced by some credits. Additional Medicare Tax: High-income earners may also have to pay an additional 0.9% tax on wages,