Illinois State Income Tax: 2026 Rate, Exemptions & Rules
Illinois taxes income at a flat 4.95% — no brackets, no standard deduction, just one rate plus personal exemptions of $2,925 per person. It’s a middle-of-the-road flat tax: higher than Pennsylvania’s 3.07%, lower than the top rates in neighboring graduated states.
This guide covers the 2026 IL rate, how the exemptions work, and what the flat structure means for your paycheck — plus a free Illinois income tax calculator.
The 2026 IL Rate: Flat 4.95%
Every dollar of Illinois taxable income is taxed at 4.95%. Your marginal rate and your average rate on taxable income are the same — the only thing that lowers your effective rate is the exemption subtraction.
Personal Exemptions (No Standard Deduction)
Illinois offers no standard deduction. Instead, you subtract a personal exemption for each person:
- Single: $2,925
- Married filing jointly: $5,850
- Each dependent: +$2,925
So a married couple with two kids subtracts $11,700 before the 4.95% applies. Additional exemptions exist for taxpayers 65+ or blind.
Illinois taxable income = federal AGI (with IL adjustments) − exemptions. Run your numbers in the Illinois income tax calculator.
Worked Example: Single Filer, $80,000
- Gross income: $80,000
- Less personal exemption: −$2,925
- IL taxable income: $77,075
- State tax (4.95%): $3,815.21
- Effective rate: 4.77%
Illinois Tax Quirks
No local income taxes. Unlike Pennsylvania or Ohio, Illinois municipalities can’t levy income taxes — the state figure is the whole story (though property taxes are famously high).
Retirement income is exempt. Illinois fully excludes pension, 401(k), IRA, and Social Security income — a major benefit for retirees that few states match.
Flat-tax debates continue. Illinois voters rejected a graduated-tax amendment in 2020, so the flat 4.95% remains. Any future change would require another constitutional amendment.
Frequently Asked Questions
Is Illinois a flat-tax state?
Yes — 4.95% on all taxable income, with personal exemptions ($2,925/person) as the only broad subtraction. No brackets, no standard deduction.
What’s the difference between the exemption and a standard deduction?
Functionally similar (both reduce taxable income), but Illinois’ exemption is per-person rather than a fixed household amount — so larger families get a bigger subtraction.
Does Chicago have a city income tax?
No. Illinois does not allow local income taxes, so Chicago residents pay only the state 4.95% on income (plus notably high property and sales taxes).
How do I estimate my Illinois tax?
Use the free Illinois income tax calculator — enter income, filing status, and dependents. For a regional comparison, see the Pennsylvania income tax calculator.
Estimates only — not tax advice. Verify with the Illinois Department of Revenue or a tax professional.
