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
Working Tax Credit from the earlier benefit for working families known as Family Credit (FC), which had been in operation since 1986. The WFTC shared its assessment of means and period of renewal (6 months) with FC but moved towards a tax credit approach styled on schemes in other countries, which used an annual declaration of income to assess entitlement for a whole year. Tax credits also replaced the child elements in means tested benefits, the Children's Tax Credit in the tax system, and disabled persons tax credit. In 2014 WTC and CTC combined cost £30 billion per year. The basic operation of