2025 Illinois Income Tax Brackets
Illinois (IL) levies a flat income tax rate of 5.0% for 2025. Brackets apply to taxable income after the state standard deduction.
Single Filer · 2025
Also applies to married filing separately in most states.
| Rate | Taxable income |
|---|---|
| 5.0% | $0 and up |
Married Filing Jointly · 2025
Flat rate applies to all filing statuses
| Rate | Taxable income |
|---|---|
| 5.0% | $0 and up |
Effective rate at common income levels (single)
Effective rate = total Illinois income tax owed divided by gross income, after the state standard deduction. Federal tax and FICA are not included here.
| Gross income | Illinois tax | Effective rate | Marginal rate |
|---|---|---|---|
| $50,000 | $2,475 | 5.0% | 5.0% |
| $75,000 | $3,713 | 5.0% | 5.0% |
| $100,000 | $4,950 | 5.0% | 5.0% |
| $150,000 | $7,425 | 5.0% | 5.0% |
| $250,000 | $12,375 | 5.0% | 5.0% |
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The top Illinois bracket is 5.0%, beginning at the first dollar of taxable income.
At $100,000 of gross income (single filer), the Illinois effective income tax rate is approximately 5.0% — about $4,950 in state tax after the $0 standard deduction.
The Illinois standard deduction for 2025 is $0 for single filers and $0 for married filing jointly.
Flat rate applies to all filing statuses in Illinois for 2025.
Illinois publishes annual inflation adjustments to bracket thresholds through its Department of Revenue. Rate changes typically require legislative action. Verify the latest figures against the current year instructions.
Reading Illinois's bracket structure
Illinois uses a flat-rate income tax structure for 2025: a single rate of 4.95% applies to all taxable income above the standard deduction, regardless of filing status or income level. Flat-tax states (Colorado, Illinois, Indiana, Kentucky, Massachusetts, Michigan, North Carolina, Pennsylvania, Utah) generate predictable per-dollar tax revenue and simplify withholding calculations, but they produce the same marginal rate for a six-figure earner as for a minimum-wage worker — a feature critics describe as regressive relative to a progressive bracket structure.
At 4.95%, Illinois's top marginal rate is on the lower end of state income taxes — similar to Arizona, Mississippi, North Dakota, and a handful of other states that combine a flat or near-flat structure with relatively low rates. Low-top-rate states typically generate a larger share of total state revenue from sales tax, property tax (via local taxing authorities), or severance tax on natural resources than high-rate states do.
Tax brackets and deduction amounts on this page are the official figures published by the Illinois Department of Revenue (or equivalent state tax authority) for the 2025 tax year. They are subject to mid-year revision when the state legislature passes a tax bill, and we update the figures within 30 days of any published change. For year-end planning calculations close to filing season, cross-reference against the state department's current published bracket table before filing.
Illinois 2025 income tax brackets from official state Department of Revenue publications, cross-checked against the Tax Foundation's State Individual Income Tax Rates and Brackets report. Effective-rate calculations use the standard deduction and progressive bracket math; itemized deductions, credits, and locality taxes are not included. Not tax advice; consult a qualified tax professional before filing.