Illinois has a top marginal income tax rate of 4.95% for 2026. See the full brackets, standard deduction, and how it stacks up against the national average.
Last updated: May 2026 · Data: state revenue departments, IRS, BLS
Illinois uses a flat income tax system administered by the Illinois Department of Revenue. The top marginal rate for 2026 is 4.95%.
| Taxable Income | Tax Rate (2026) |
|---|---|
| All taxable income | 4.95% |
Illinois income tax starts from your taxable income after deductions. For 2026 (2025 tax year), the federal standard deduction is $15,000 for single filers and $30,000 for married filing jointly, which reduces the income subject to federal tax.
| Standard Deduction (2026) | Amount |
|---|---|
| Federal - Single | $15,000 |
| Federal - Married Filing Jointly | $30,000 |
| Federal - Head of Household | $22,500 |
State standard deductions, personal exemptions, and credits vary and may differ from the federal amounts above. Confirm Illinois figures with the Illinois Department of Revenue.
| Benchmark | Top Marginal Rate |
|---|---|
| Illinois (2026) | 4.95% |
| National average - all 50 states | 4.86% |
| National average - 41 states with an income tax | 5.93% |
| Highest in the U.S. (California) | 13.3% |
| Lowest among states that tax income | 2.5% |
| States with no income tax | 0% (9 states) |
At 4.95%, Illinois's top rate is above the national average of 4.86% (all 50 states).
Illinois has a constitutionally mandated flat income tax rate, currently set at 4.95%. A 2020 ballot measure to allow graduated rates was rejected by voters. The state also does not tax retirement income.
| Illinois Tax Snapshot | 2026 |
|---|---|
| Top Income Tax Rate (2026) | 4.95% |
| Income Tax Structure | Flat rate |
| State Sales Tax | 6.25% |
| Minimum Wage | $15.00/hour |
| Median Household Income | $78,000 |
| Tax Agency | Illinois Department of Revenue |
Run the numbers for Illinois with our free calculators:
See how nearby states tax income in 2026:
Illinois has a top marginal state income tax rate of 4.95% for 2026. It is administered by the Illinois Department of Revenue.
Illinois uses a flat income tax rate, meaning the same percentage applies to all taxable income.
Illinois applies a single flat rate, so there is effectively one bracket.
The 2026 federal standard deduction is $15,000 for single filers and $30,000 for married filing jointly. Illinois state deductions, exemptions, and credits can differ; verify current figures with the Illinois Department of Revenue.
At 4.95%, Illinois's top rate is above the national average of 4.86% (all 50 states). The national average top marginal rate is 4.86% across all 50 states and 5.93% among the 41 states that levy an income tax.
State income tax in Illinois is collected by the Illinois Department of Revenue. Federal income tax and FICA (Social Security and Medicare) are paid separately to the IRS.