State Income Tax
Illinois imposes a state income tax using a flat rate of 4.95% on all taxable income regardless of income level. The filing deadline is 2026-04-15. Social Security benefits are exempt from Illinois state income tax. Retirement income is generally exempt from state tax. Most retirement and pension income is exempt from Illinois tax.
Retirement Income Details
Most retirement and pension income is exempt from Illinois tax.
Does Illinois have a state income tax?
Yes. Illinois has a state income tax with a flat rate of 4.95%.
What is the Illinois income tax rate?
Illinois uses a flat tax rate of 4.95% on all taxable income. This means all taxpayers pay the same rate regardless of how much they earn.
Is Social Security taxed in Illinois?
No. Illinois does not tax Social Security benefits, which can be significant for retirees living on fixed incomes.
Is retirement income taxed in Illinois?
Illinois generally exempts retirement income from state tax. Most retirement and pension income is exempt from Illinois tax.
When is the Illinois income tax filing deadline?
The Illinois state income tax filing deadline is 2026-04-15. You can file and pay through the official Illinois Department of Revenue portal.
What is the standard deduction in Illinois?
Illinois's standard deduction is not available for single filers. A personal exemption of $2,850 (single) may also apply.
How does Illinois income tax compare to neighboring states?
Illinois's top rate of 4.95% is in the moderate range nationally. Use the comparison table above to see how neighboring states compare.
Official Payment Portal
Illinois Department of Revenue
Last verified: 2026-03-31 · Always consult a tax professional before making financial decisions.