Illinois variant. This is a Illinois-specific version of the Income Tax Calculator, using pre-defined local figures (tax rates, median home and income values, and typical regional costs). For the full formula, methodology, and FAQ, open the main Income Tax Calculator.
Illinois income tax (Flat 4.95%) stacks on top of federal tax. Understanding both layers is essential to estimating your total Illinois tax bill.
Illinois state income tax structure
Illinois taxes income at Flat 4.95%, with a top marginal rate of 4.95%. Like the federal system, only income within each bracket is taxed at that bracket's rate.
Federal brackets (10%–37%) apply nationwide. Combine your federal effective rate with the Illinois rate to find your true marginal tax on the next dollar earned.
About taxes and housing in Illinois
Illinois applies a single flat income tax rate to all earners, as its constitution prohibits a graduated income tax.
Illinois has among the highest effective property tax rates in the nation, which is a major factor in overall housing costs.
Illinois's economy is anchored by Chicago as a center for finance, transportation, and manufacturing, with agriculture dominant downstate.
Worked example: state tax on $78,433
Using the 4.95% top rate as a ceiling, state income tax on $78,433 is at most about $3,882; the actual figure is lower after brackets and deductions.
Quick reference
- State income tax: Flat 4.95%
- State sales tax: 6.25% (plus 2.59% avg local)
- Median home value: $270,000
- Median household income: $78,433
- Effective property tax rate: 2.08%
- Avg auto insurance: $1,652/yr
Frequently Asked Questions
Does Illinois have state income tax?
Yes - Flat 4.95%, topping out at 4.95%.
What is the top tax rate in Illinois?
The top marginal state rate is 4.95%.