Illinois Income Tax Calculator
Estimate your 2025 Illinois state and federal income tax. Includes Illinois tax brackets, a worked dollar example, and filing tips.
Illinois State Income Tax Overview
Illinois imposes a flat income tax rate of 4.95% on all net income, regardless of filing status or income level. Illinois does not allow a standard deduction or graduated brackets, but it does provide a personal exemption of $2,425 per return. One notable feature of Illinois tax law is that most retirement income — including Social Security, pension income, and distributions from qualified retirement plans like 401(k)s and IRAs — is fully exempt from state income tax. Illinois has a relatively high combined state and local sales tax burden, and property taxes are among the highest in the nation, particularly in the Chicago metro area.
Illinois Income Tax Rate (2025)
Illinois uses a flat income tax rate — the same percentage applies to all taxable income regardless of how much you earn.
Source: Illinois Department of Revenue
What a Illinois Resident Actually Pays: A Worked Example
| Taxable Income | $65,000.00 |
| Illinois Flat Rate | 4.95% |
| Estimated State Tax | $3217.50 |
| Effective Rate | 4.95% |
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Frequently Asked Questions — Illinois Income Tax
Does Illinois have a state income tax?
Yes. Illinois imposes a state income tax with a flat rate of 4.95%. This is separate from your federal income tax obligation.
What is the Illinois income tax rate for 2025?
Illinois uses a flat income tax rate of 4.95% on all taxable income, regardless of income level or filing status.
Do I have to file a Illinois state tax return?
Most full-year Illinois residents with income above the state filing threshold must file a state return. Check the Illinois Department of Revenue for current thresholds and requirements.
How accurate is this Illinois state tax estimate?
This is a planning estimate. The state result uses Illinois's published brackets but does not account for all state deductions, credits, exemptions, or local taxes. Verify with official Illinois tax forms or a qualified tax professional.
Does this calculator include federal income tax?
Yes. The results show your estimated Illinois state income tax and your federal income tax using 2025 federal brackets — your full combined picture in one place.
Where can I find official Illinois tax forms?
Official forms, instructions, and filing guidance are available at the Illinois Department of Revenue.
Understanding Your Illinois Tax Estimate
Your results show both your estimated federal income tax and your estimated Illinois state income tax as a combined picture. Here is how to read them and what to do next.
Federal vs. State Tax: Two Separate Bills
Federal income tax is owed to the IRS and is the same rate schedule for all U.S. residents regardless of where you live. Illinois state income tax is a separate obligation paid to the Illinois Department of Revenue. You file two separate returns — one federal (Form 1040) and one state — though they are often prepared together using tax software.
How the Estimate Is Calculated
This calculator applies the 2025 federal tax brackets to your taxable income (gross income minus the standard or itemized deduction), then applies Illinois's published state brackets to estimate your state liability. The result is a planning estimate — not a filed return. It does not account for all credits, deductions, or individual circumstances that could change your actual bill.
Marginal Rate vs. Effective Rate
Your marginal rate is the rate on your last dollar of income — it is the highest bracket you reach, not what you pay on all income. Your effective rate is your total tax divided by gross income, and is almost always meaningfully lower. For example, a single filer earning $75,000 may be in the 22% federal bracket but pay an effective federal rate of only 14-15%. The same principle applies to Illinois state brackets.
3 Ways to Reduce Your Illinois Tax Bill
- Maximize pre-tax retirement contributions. Traditional 401(k) and IRA contributions reduce your federal taxable income. Many states, including Illinois, also exclude these contributions from state taxable income, reducing both bills simultaneously.
- Claim all applicable deductions and credits. Many states offer credits for property taxes, dependent care, education, and energy-efficient home improvements that are separate from federal credits. Check the Illinois Department of Revenue for Illinois-specific credits.
- Consider the standard vs. itemized deduction. Some states allow itemized deductions even if you take the federal standard deduction — or have their own standard deduction amounts that differ from federal. Checking the state-specific rules can sometimes reveal additional savings.
What to Do After Getting Your Estimate
- If you expect to owe money, consider adjusting your W-4 withholding or making a state estimated tax payment to avoid a balance due at filing time.
- If you are self-employed, your SE tax is separate — use our self-employment tax calculator to estimate that additional obligation.
- To verify your numbers, use the official Illinois tax forms or consult a qualified tax professional familiar with Illinois tax law.
Disclaimer: Estimates for educational purposes only. State tax results are approximations based on published bracket data and do not account for all deductions, credits, exemptions, local taxes, or individual situations. Not tax, legal, or financial advice. Consult the Illinois Department of Revenue or a qualified tax professional for guidance specific to your situation.