Illinois State Tax Calculator 2026
Estimate your Illinois state income tax and take-home pay for tax year 2026.
Last updated: November 2025 · Source
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Illinois 2026 tax overview
Constitutional flat 4.95%; no std deduction. Personal exemption ~$2,925 phases out at high income.
Breakdown
Illinois income tax brackets, 2026
Illinois charges one rate on all taxable income. Figures are for single filers unless the state uses one schedule for all statuses.
| Taxable income | Rate | Tax on this bracket |
|---|---|---|
| Over $0 | 4.95% | 4.95% of everything above $0 |
Brackets apply to income after the Illinois standard deduction of $0 single and $0 married filing jointly, which is separate from the federal standard deduction.
Frequently Asked Questions
What are the 2026 Illinois income tax rates?
Illinois charges a flat 4.95% on taxable income for 2026. Constitutional flat 4.95%; no std deduction. Personal exemption ~$2,925 phases out at high income.
At what income does the top Illinois tax rate start?
Illinois has a single rate, so it applies from the first dollar of taxable income above the standard deduction. There is no higher bracket to reach.
What is the 2026 Illinois standard deduction?
Illinois allows a state standard deduction of $0 for single filers and $0 for married filing jointly in 2026. This is separate from the federal standard deduction, which is $16,100 and $32,200 respectively.
Does Illinois have tax reciprocity with neighbouring states?
Yes. Illinois has reciprocal agreements with Iowa, Kentucky, Michigan, Wisconsin. If you live in one of those states and work in Illinois, you file and pay only where you live, and you give your employer the relevant non-residence certificate so Illinois tax is not withheld. Without that form the tax is withheld anyway and you have to file a Illinois return to get it back.
Does Illinois tax Social Security and retirement income?
Illinois does not tax retirement income at all. Not Social Security, not pensions, not 401(k) or IRA withdrawals. It is one of the most generous treatments in the country.
What surprises people most about Illinois income tax?
The flat 4.95% rate is written into the state constitution, which is why the 2020 attempt to introduce graduated rates required a constitutional amendment (it failed).