Illinois Income
Tax Rates & Rules
Illinois has a flat state income tax rate of 4.95%, applied to all taxable income regardless of income level.
Illinois Flat Income Tax Rate
Illinois tax year rates, most recently confirmed by the state Department of Revenue.
All Filing Statuses
| Taxable Income | Rate |
|---|---|
| All taxable income | 4.95% |
Illinois applies a single flat rate to all taxable income, regardless of income level or filing status.
Sources: Illinois DOR — Tax Rates. Last verified: August 14, 2026.
How Illinois Income Tax Works
Placeholder text — full content about how Illinois income tax is calculated, withheld from paychecks and filed will be added here.
Frequently Asked Questions
Placeholder question about Illinois income tax rates?
Placeholder answer text — real FAQ content will be added here.
Placeholder question about Illinois income tax withholding?
Placeholder answer text — real FAQ content will be added here.
Placeholder question about filing Illinois state income tax?
Placeholder answer text — real FAQ content will be added here.