Income tax rule
Illinois uses 4.95% flat income tax rate in the current TaxGuide Pro calculator data.
Single example
$60,000 single taxable income -> about $2,970 state income tax before credits.
Joint example
$120,000 married filing jointly taxable income -> about $5,940 state income tax before credits.
Deductions and exemptions
Illinois deductions and exemptions depend on filing status and state instructions; verify the current return before filing.
Credits to review
Review dependent, household, income-based, and other Illinois credits in the state credit finder, then confirm eligibility in official instructions.
Filing deadline
For a 2026 return filed in 2027, confirm the due date in published Illinois instructions. State deadlines and disaster relief can differ from federal dates.
Refund processing
Illinois does not guarantee one refund date for every return. E-filed, accurate returns with direct deposit are generally processed faster than paper or reviewed returns.