Legal history of income tax in the United States adopted an income tax modeled on the tax instituted in England. The British theory was that you tax the income from property, and not the property itself; thus, sales of property were not subject to taxation. In order to help pay for its war effort in the American Civil War, the United States government imposed its first personal income tax, on August 5, 1861, as part of the Revenue Act of 1861. Tax rates were 3% on income exceeding $600 and less than $10,000, and 5% on income exceeding $10,000. This tax was repealed and replaced by another income tax
Income tax in the United States insurance (Social Security) taxes in 2016. The table below also does not reflect changes, effective with 2013 law, which increased the average tax paid by the top 1% to the highest levels since 1979, at an effective rate of 33%, while most other taxpayers have remained near the lowest levels since 1979. Income tax is imposed as a tax rate times taxable income. Taxable income is defined as gross income less allowable deductions. Taxable income as determined for federal tax purposes may be modified for state tax purposes. The Internal Revenue Code states that "gross income means all income from