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Illinois Flat Tax Formula:
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Illinois uses a flat state income tax rate of 4.95% for 2025. This means all taxable income is taxed at the same rate regardless of income level, making Illinois one of the few states with a flat income tax structure.
The calculator uses the Illinois flat tax formula:
Where:
Explanation: The calculation multiplies your taxable income by the flat tax rate of 4.95% to determine your Illinois state income tax liability.
Details: Accurate tax calculation is essential for financial planning, budgeting, tax preparation, and ensuring compliance with Illinois state tax laws. Understanding your tax liability helps with proper withholding and estimated tax payments.
Tips: Enter your taxable income in USD. This should be your total income after adjustments, deductions, and exemptions. The calculator will compute your Illinois state income tax based on the 4.95% flat rate.
Q1: What is considered taxable income in Illinois?
A: Taxable income includes wages, salaries, tips, interest, dividends, business income, and other earnings, minus allowable deductions and exemptions.
Q2: Are there any deductions or credits available?
A: Illinois offers various deductions and credits, including property tax credits, education expenses, and retirement income exclusions for qualifying taxpayers.
Q3: How does Illinois compare to other states?
A: Illinois' 4.95% flat rate is moderate compared to other states. Some states have no income tax, while others have progressive rates up to 13.3%.
Q4: When are Illinois state taxes due?
A: Illinois state income taxes are typically due April 15th, matching the federal tax deadline, with extensions available when needed.
Q5: Is this calculator for estimated taxes only?
A: This calculator provides an estimate of your Illinois state income tax liability. For precise calculations, consult with a tax professional or use official Illinois tax forms.