Illinois State Tax Calculator
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Illinois enforces a statutory flat state individual income tax rate of 4.95% on all state net income, as mandated by the Illinois State Constitution. Unlike states with progressive tax brackets, every dollar of taxable income in Illinois is taxed at the same uniform 4.95% rate, regardless of filing status or income level.
Our free Illinois Tax Calculator computes your Illinois taxable income, applies state personal exemption allowances, computes the 5% Illinois property tax credit, and calculates your net take-home paycheck.
How to Calculate Illinois State Income Tax
Illinois state income tax starts with federal Adjusted Gross Income (AGI), incorporates Illinois-specific additions and subtractions, subtracts standard personal exemptions, and applies the flat 4.95% tax rate.
The Illinois Taxable Income Formula:
Illinois Base Income = Federal AGI ± Illinois Additions/Subtractions
Illinois Taxable Income = Illinois Base Income - Total Personal Exemption Allowances
The Illinois Income Tax Liability Formula:
Gross Illinois State Tax = Illinois Taxable Income × 4.95%
Net Illinois State Tax = Gross Illinois State Tax - Illinois Property Tax Credit (5%) - K-12 Education Tax Credits
Illinois Personal Exemption Allowance Rules:
- Standard Personal Exemption: $2,775 per taxpayer and eligible dependent.
- Exemption Allowance Phaseout: Personal exemptions are completely eliminated for single filers with AGI exceeding $250,000 (or $500,000 for married joint filers).
- Illinois Property Tax Credit: State tax credit equal to 5.0% of Illinois real estate property taxes paid on a primary residence (phased out above $250k/$500k AGI).
Illinois Personal Exemption Amounts & Tax Rates
Summary of Illinois state tax parameters across filing statuses:
| Filing Status | State Tax Rate | Personal Exemption Allowance | Exemption Phaseout Threshold |
|---|---|---|---|
| Single Filer | 4.95% Flat Rate | $2,775 | $250,000 AGI |
| Married Filing Jointly | 4.95% Flat Rate | $5,550 ($2,775 per spouse) | $500,000 AGI |
| Dependent Allowance (per child) | N/A | +$2,775 per Dependent | $250k / $500k AGI |
Step-by-Step Calculation Example
Consider a Single Filer in Illinois earning a $75,000 annual salary who pays $4,000 in Illinois residential property taxes:
- Federal AGI: $75,000
- Illinois Personal Exemption: $2,775
- Annual Property Tax Paid: $4,000
Step 1: Compute Illinois Taxable Income
Illinois Taxable Income = $75,000 - $2,775 = $72,225.00
Step 2: Compute Gross Illinois State Tax (4.95% Flat Rate)
Gross Illinois Tax = $72,225 × 0.0495 = $3,575.14
Step 3: Calculate Illinois Property Tax Credit (5%)
Property Tax Credit = $4,000 property tax × 5.0% = $200.00
Step 4: Compute Net Illinois State Tax Owed
Net Illinois State Tax = $3,575.14 - $200.00 = $3,375.14
Effective State Tax Rate = ( $3,375.14 / $75,000 ) × 100 = 4.50%
Frequently Asked Questions (FAQ)
Does Illinois tax retirement income or pensions?
No. Illinois is highly tax-friendly toward retirees. Illinois does not tax Social Security benefits, qualified 401(k)/IRA distributions, government pensions, or private employer pension plans.
What is the Illinois Property Tax Credit?
The Illinois Property Tax Credit allows homeowners to claim a non-refundable state tax credit equal to 5.0% of real estate property taxes paid on their primary Illinois residence during the tax year (subject to AGI income limits).
Are local city sales taxes high in Chicago, Illinois?
Yes. Combined sales taxes in Chicago, Illinois reach 10.25%, combining the Illinois baseline state sales tax (6.25%), Cook County tax, City of Chicago tax, and RTA transit district taxes.