Illinois State Income Tax Overview
Illinois (IL) state income tax rate: 4.95% flat (flat rate system)
Illinois Income Tax Brackets (2026)
Flat 4.95% on all net income — Illinois constitution requires a flat income tax rate
Illinois is constitutionally required to have a flat income tax. A 2020 ballot measure to allow graduated rates was rejected by voters. The 4.95% rate applies to all income, and Illinois does not allow a personal exemption for higher earners.
Median Household Income in Illinois
The median household income in Illinois is $72,205. Illinois' median income is bolstered by the Chicago metro but dragged down by slower-growth downstate regions. High property taxes are a significant additional burden on top of the income tax.
How to Use This Calculator for Illinois
- Enter your gross income and filing status
- The calculator applies Illinois's flat income tax rate of up to 4.95% flat
- Subtract your standard deduction and any applicable credits
- Review your estimated state and federal tax liability
Frequently Asked Questions
What is the Illinois state income tax rate?
Illinois has a flat income tax with a top rate of 4.95% flat. Flat 4.95% on all net income — Illinois constitution requires a flat income tax rate.
How does Illinois's income tax compare to the national average?
Illinois's top income tax rate of 4.95% flat applies to a flat rate system. Illinois is constitutionally required to have a flat income tax. A 2020 ballot measure to allow graduated rates was rejected by voters. The 4.95% rate applies to all income, and Illinois does not allow a personal exemption for higher earners.
What is the median household income in Illinois?
The median household income in Illinois is $72,205. Illinois' median income is bolstered by the Chicago metro but dragged down by slower-growth downstate regions. High property taxes are a significant additional burden on top of the income tax.
Is this state income tax calculator free to use for Illinois?
Yes, this state income tax calculator is 100% free with no signup required. It includes Illinois-specific tax rates and calculates your estimated state and federal tax liability instantly.