Illinois State Income Tax Calculator
Estimate your state income tax bill by filing status.
This is a simplified estimate of Illinois state income tax based on published bracket rates — it does not account for state-specific standard deductions, exemptions, or credits, which vary by state and filing status.
Illinois income tax
How Illinois taxes income
Illinois uses a flat income tax rate of 4.95% — everyone pays the same rate regardless of income level, which keeps the math simple compared to a bracket system.
Illinois generally does not tax common forms of retirement income like pensions and 401(k)/IRA withdrawals, which can make it more attractive for retirees.
Frequently asked questions
What's the difference between marginal and effective tax rate?+
Your marginal rate is the rate applied to your last dollar of income (the top bracket you reach). Your effective rate is your total tax divided by total income — usually lower than your marginal rate under a progressive system.
Does this include deductions and credits?+
This calculator applies published bracket rates to your taxable income but doesn't model state-specific standard deductions, exemptions, or credits, which can meaningfully lower your actual bill.
How much state income tax on $75,000 in Illinois?+
On $75,000 of taxable income in Illinois, estimated state income tax is about $3,713 — a 5.0% effective rate and a 5.0% marginal rate on the last dollar earned.