Illinois charges 4.95% flat state income tax. Use the w-4 withholding calculator pre-loaded with Illinois rates.
Open W-4 Withholding Calculator →Getting your W-4 right in Illinois is important because you need to coordinate federal withholding with Illinois's flat 4.95% state withholding. If your W-4 is set too conservatively, you lend the government an interest-free loan; too aggressively, and you face an underpayment penalty. This calculator helps you dial in the right federal withholding amount given your Illinois state tax situation.
Illinois levies a flat 4.95% state income tax on all taxable income regardless of how much you earn. This makes tax planning straightforward: for every additional dollar you earn, 4.95 cents goes to Illinois. Illinois does not impose local income taxes, so the 4.95% flat rate is the only state-level income tax you owe.
The table below shows what you actually keep at five salary levels in Illinois, accounting for federal tax, FICA, and Illinois's flat 4.95% state tax.
See how Illinois compares to other Midwest states. Each link takes you to the w-4 withholding calculator landing page for that state.
For a comprehensive breakdown of Illinois’s tax structure, salary comparisons, cost-of-living analysis, and more, visit the full Illinois take-home pay page.