State income tax is imposed at a fixed or graduated rate on taxable income of individuals, corporations, and certain estates and trusts. The rates vary by state. Taxable income conforms closely to federal taxable income in most states, with limited modifications. The states are prohibited from taxing income from federal bonds or other obligations. Most do not tax Social Security benefits or interest income from obligations of that state. Several states require different useful lives and methods be used by businesses in computing the deduction for depreciation. Many states allow a standard deduction or some form of itemized deductions. States allow a variety of tax credits in computing tax.
