Illinois Tax Calculator
Calculate Illinois state income tax for 2025 using the flat 4.95% rate. Enter income and filing status to get tax owed, effective rate, and breakdown charts.
About This Calculator
The Illinois Tax Calculator helps residents estimate their Illinois state income tax liability for 2025. Illinois uses a flat income tax rate of 4.95% -- one of the few states with a single-rate system -- making state tax calculations straightforward compared to progressive-rate states.
This calculator applies the Illinois personal exemption ($2,925 for single filers, $5,850 for married filing jointly), which phases out completely for higher-income earners (over $250,000 single / $500,000 married). The result shows your taxable income after the exemption, the Illinois state tax owed, and your effective tax rate.
Illinois Tax Facts
Illinois has no local or county income taxes. In addition to the 4.95% state income tax, Illinois residents pay federal income tax (progressive 10%-37%) and FICA taxes (7.65% total for Social Security and Medicare). Illinois property taxes are assessed at the county level and average about 1.8% of home value, among the highest in the nation.
This calculator covers only the Illinois state income tax component. For a comprehensive estimate including federal taxes and FICA, use our Income Tax Calculator or FICA Tax Calculator (US).
Frequently Asked Questions
What is the Illinois state income tax rate for 2025?
Illinois has a flat state income tax rate of 4.95% for 2025. Unlike progressive tax systems, all taxpayers pay the same rate regardless of income level. This flat rate applies to single filers, married couples filing jointly, and married couples filing separately.
How does the personal exemption work for Illinois taxes?
Illinois offers a personal exemption of $2,925 for single filers and $5,850 for married couples filing jointly. However, the personal exemption is phased out for higher-income taxpayers: it is fully eliminated when adjusted gross income exceeds $250,000 for single filers or $500,000 for married couples filing jointly.
Does Illinois have local income tax?
No, Illinois does not have any local or county income taxes. Illinois residents only pay federal income tax, Illinois state income tax at 4.95%, and FICA taxes (Social Security at 6.2% and Medicare at 1.45%).
What is the property tax rate in Illinois?
Illinois has some of the highest property tax rates in the US, with an average effective rate of approximately 1.8%. Rates vary significantly by county, from around 0.98% in Pulaski County to 2.95% in Lake County. Property tax is assessed at the county level, not the state level.
How do I calculate my Illinois state income tax?
To calculate your Illinois state income tax, subtract your personal exemption ($2,925 for single, $5,850 for married filing jointly) from your adjusted gross income to get your taxable income. Then multiply your taxable income by the flat 4.95% rate. For example, a single filer with $50,000 AGI pays ($50,000 - $2,925) x 4.95% = $2,330 in Illinois state income tax.
Can I deduct my Illinois state income tax on my federal return?
Yes, Illinois state income tax paid is deductible as a state and local tax (SALT) deduction on your federal income tax return. However, the SALT deduction is capped at $10,000 ($5,000 for married filing separately) under current federal tax law.
When are Illinois state income tax returns due?
Illinois state income tax returns are due on the same date as federal returns, typically April 15. If April 15 falls on a weekend or holiday, the deadline moves to the next business day. An automatic 6-month extension is available by filing Form IL-505-I.
What is the difference between federal and Illinois state income tax?
Federal income tax uses progressive tax brackets ranging from 10% to 37% based on income level, with different brackets for different filing statuses. Illinois uses a flat 4.95% rate that applies to all taxpayers regardless of income. Additionally, Illinois offers a personal exemption that phases out at higher incomes, while the federal system uses a standard deduction.