Illinois Tax Calculator

Illinois State Income Tax Overview

Illinois levies a flat state individual income tax rate of 4.95% on net taxable income. Unlike states with progressive tax brackets, every eligible Illinois taxpayer pays the same percentage regardless of income tier.

How Illinois Income Tax is Calculated

Calculating your state income tax liability involves subtracting state personal exemptions from gross income to determine the taxable base.

• Flat Tax Rate: 4.95% applied to net taxable income.
• Personal Allowance Exemption: Standard personal exemption allowance per taxpayer and qualified dependent (e.g. $2,775 per exemption).
• Taxable Base: Gross Income - Total Personal Exemptions.
• State Tax Liability: Taxable Base × 0.0495.

Illinois Tax Credits & Deductions

Illinois offers several state credits that can reduce final tax liability, including the Illinois Property Tax Credit (5% of Illinois property taxes paid on a primary residence), the K-12 Education Expense Credit, and the Earned Income Tax Credit (EITC).

For overall federal and state tax planning, check out our Income Tax Calculator or calculate workplace earnings using the Illinois Overtime Calculator.