Illinois State Tax Calculator (2026)
Estimate your Illinois state income tax for 2026 using the published bracket schedule and standard deduction. State tax is separate from federal tax.
Reviewed by Teja K, CPA · last reviewed . General information, not tax advice for your situation. A calculator is an estimate, not a filed return. How we research and review this.
Before the state standard deduction
Income entered
$0
Standard deduction
$0
Taxable
$0
Illinois tax
$0
Separate from your federal bill
Effective rate
0.00%
Marginal rate 4.95%
- Illinois grants no standard deduction, so the rate applies from the first dollar of taxable income.
Not included in this figure
- Personal exemption: $2,925 single, $5,850 joint, $2,925 per dependent — not applied — this estimate is therefore slightly high
- Local and municipal income tax: No local rates are modelled. — a resident of a city that levies its own income tax will owe more
- State credits, subtractions and addbacks: State-specific adjustments to income are out of scope. — can move the result in either direction
Tax year 2026. Illinois tax only — federal tax is separate. Rate figures as of January 1, 2026.
How Illinois taxes income
Illinois charges flat 4.95%. State tax is a separate calculation from your federal return rather than a share of it — Illinois sets its own schedule and its own definition of taxable income.
- Rate: Flat 4.95% on net income, all filers
- Standard deduction: None — a personal exemption applies instead
- Personal exemption: $2,925 single / $5,850 joint, plus $2,925 per dependent
- Retirement income: Qualifying retirement distributions are excluded from Illinois income
Rate figures are as of January 1, 2026 and come from the published Tax Foundation compilation; they have not been independently checked against Illinois Department of Revenue. States do change rates mid-year, so confirm a figure there before relying on it.
What catches people out in Illinois
- The flat rate is required by the Illinois constitution. A 2020 ballot measure to permit graduated rates was rejected, so a move to brackets would need a constitutional amendment rather than ordinary legislation.
- The retirement income exclusion covers qualifying distributions from 401(k) and similar plans, IRAs and most pensions. It is subtracted on the Illinois return rather than applied automatically, so it has to be claimed.
- Illinois has reciprocity agreements with Iowa, Kentucky, Michigan and Wisconsin. Residents of those states working in Illinois generally pay tax only at home on those wages, and vice versa.
- Illinois grants a credit for income tax paid to other states, which matters for anyone working across the Chicago metropolitan area into Indiana or Wisconsin.
What this estimate leaves out
Three things are deliberately outside this calculation, because they change more often than annually and a confident wrong number does real damage on a tax page.
- The personal exemption — $2,925 single, $5,850 joint, $2,925 per dependent — is not applied, so the figure runs slightly high.
- Local and city income tax is not included. New York City is the significant one nationally.
- State-specific credits, subtractions and income addbacks are out of scope and can move the result either way.
If you have income in India, Illinois is where treaty relief runs out
States are not parties to the India-US tax treaty, and a state credit for "taxes paid to other jurisdictions" almost always means other US states rather than other countries.
So NRO interest, Indian rental income or a gain on Indian shares can be taxed by Illinois with no credit for the Indian tax deducted at source — even though Form 1116 largely neutralises that same tax federally.
The treatment is not uniform across states, and it has been verified individually rather than assumed. The state guide sets out this state's position with the primary source behind it.
Sources
Frequently Asked Questions
Does Illinois have a state income tax?
Yes — Illinois charges flat 4.95%. Figures are as of January 1, 2026.
Is Illinois tax on top of federal tax?
Federal tax applies regardless of which state you live in, and is calculated separately. Illinois tax is additional to it, and uses its own brackets and its own deduction rather than a share of your federal bill.
I moved to or from Illinois during the year. Does this work?
Not directly. A part-year move usually means a part-year return in each state with income apportioned between them, and the state you left applies its own residency test rather than accepting a new address. Use this to size the rates, then treat the apportionment as a separate question.
What filing statuses does this cover?
Single and married filing jointly. Those are the only two schedules published in the sourced data behind this calculator, so head of household and married filing separately are left out rather than approximated from a schedule nobody verified.
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