What is the Illinois Income Tax Calculator?
In short
Illinois taxes all taxable income at a flat 4.95% rate rather than progressive brackets, so a higher salary doesn't push you into a higher state rate. On a $75,000 salary, a single filer keeps about $58,025 after $7,670 federal, $3,568 Illinois state tax and $5,738 FICA — a 22.6% effective rate.
This Illinois income tax calculator estimates your total tax — federal brackets + FICA (7.65%) + Illinois's flat 4.95% income tax. Illinois has taxed individual net income at 4.95% since July 1, 2017, and employers withhold the same 4.95% from wages after the employee's allowances.
How to use this calculator
- 1Enter your annual gross income.
- 2Choose your filing status (single, married, or head of household).
- 3Illinois is pre-selected — switch states to compare.
- 4Enter pre-tax deductions (401k, HSA) and any itemized deductions.
- 5Read your federal tax, state tax, FICA, total, and effective rate.
The formula
- AGI
- — Gross income minus pre-tax deductions
- taxable income
- — Federal: AGI minus the standard or itemized deduction. Illinois: federal AGI, adjusted by Illinois additions and subtractions, minus the exemption allowance
- federal tax
- — Federal income tax from progressive brackets
- IL tax
- — Illinois — a flat 4.95% income tax
- FICA
- — Social Security 6.2% + Medicare 1.45%
Worked example
The scenario
A single filer in Illinois earns $75,000 in wages, contributes nothing pre-tax, and paid $4,000 of property tax on the home they own and live in.
The result
Illinois starts from federal AGI ($75,000) and subtracts one exemption of $2,925, leaving $72,075. At 4.95% the tax is $3,567.71, which matches the calculator's $3,568. The property tax credit is 5% of the $4,000 paid, or $200.00, which brings the Illinois bill to $3,367.71. The credit can take the tax to zero but is never refunded, so it is worth the full $200.00 here. With the tax year 2025 exemption of $2,850, the same wages would have owed $3,571.43 before the credit, $3.72 more.
Common use cases
- Estimating your total tax bill before filing in Illinois
- Comparing Illinois's flat 4.95% rate against progressive-bracket states
- Seeing how pre-tax 401(k)/HSA contributions lower your tax
- federally taxed Social Security and retirement income from qualified plans, including 401(k) plans and IRAs, is subtracted from Illinois income on Form IL-1040, Line 5
Limitations & assumptions
- The exemption is the $2,925 in the Department of Revenue's 2026 withholding tables; the 2026 Form IL-1040 instructions are not yet published (tax year 2025 uses $2,850). Dependent exemptions and the extra $1,000 for a filer who is 65 or older or legally blind are not added.
- The calculator treats all income as taxable in Illinois. It does not subtract federally taxed Social Security or qualified retirement income, so a retiree's Illinois tax will usually be lower than shown.
- Illinois credits are not modelled: the 5% property tax credit, the K-12 education expense credit, the Illinois Earned Income Tax Credit, and the Child Tax Credit enacted for tax years 2024 and 2025.
- Local/city income taxes aren't included; Illinois applies its 4.95% rate statewide.
- Federal calculation uses current brackets and the standard deduction unless you itemize.
- Use it for planning; it isn't a substitute for a tax professional.
Official sources
Official publications for rules and figures this page uses. Rates and rules change, so confirm the current figures with the publisher before you rely on them:
- Illinois Department of Revenue (tax.illinois.gov)
- Illinois Department of Revenue: 2025 Form IL-1040 Instructions (tax.illinois.gov)
- Illinois Department of Revenue: Booklet IL-700-T, 2026 Withholding Tax Tables (tax.illinois.gov)
- Illinois Department of Revenue: Social Security benefits and certain retirement plans (tax.illinois.gov)
- Illinois Department of Revenue: Publication 108, Illinois Property Tax Credit (tax.illinois.gov)
- Illinois Department of Revenue: Publication 112, Education Expense Credit (tax.illinois.gov)
Frequently asked questions
What is the Illinois state income tax rate?
How much is $75,000 taxed in Illinois?
Does Illinois have a standard deduction?
How much is $100,000 taxed in Illinois?
Does Illinois tax retirement income?
What happens to the Illinois exemption above $250,000 of income?
How does the Illinois property tax credit work?
Is there an Illinois tax credit for K-12 school costs?
Disclaimer: KalkWise calculators are provided for general informational and educational purposes only and do not constitute financial, investment, tax, or legal advice. Results are estimates based on the figures you enter and the assumptions described above. Actual outcomes will vary. Consult a qualified professional before making financial decisions.