Illinois Income Tax Rate 2025
Illinois has a flat income tax rate of 4.95% on all taxable income, regardless of how much you earn. The Illinois Constitution requires a flat rate, so all taxpayers pay the same percentage.
Tax Type
Flat Rate
Income Tax Rate
4.95%
Tax Brackets
1 (flat)
How It Works
With a flat tax, your Illinois state income tax is simply 4.95% of your taxable income. Illinois does not tax retirement income, including Social Security, pensions, and distributions from 401(k) and IRA accounts.