A rate schedule is a chart that helps United States taxpayers determine their federal income tax for a particular year.
[2][5][6] Each year the United States Internal Revenue Service (IRS) updates rate schedules in accordance with guidelines that Congress established in the IRC.
[7][8] In general, the IRS bases such adjustments on inflation and cost of living increases in the previous year.
[2] The fourth column gives the range of income to which the current marginal rate applies.
Given that Congress has prescribed a system of progressive taxation, all but the lowest-earning taxpayers pay distinct rates for different parts of their income.