Illinois Income Tax
Illinois imposes a flat 4.95% income tax on all taxable net income — the same rate regardless of how much you earn. The Illinois Constitution requires a flat tax, though voters have periodically been asked to change it. Combined with high property taxes, the overall tax burden is significant.
📊 Illinois Flat Tax: How It Works
Every dollar of taxable income is taxed at exactly 4.95% — no brackets, no phase-outs, no marginal rate calculation.
🔢 Free Illinois Tax Calculators
2026 Illinois Income Tax Rate
| All Taxable Income | Rate | Who Pays |
|---|---|---|
| $0 and above | 4.95% | All taxpayers |
Illinois Personal Exemption 2026
Note: Illinois does not allow the federal standard deduction. The personal exemption above is subtracted from net income before calculating the 4.95% tax.
Illinois Property Tax 2026
Illinois has the 2nd highest property taxes in the nation, averaging 2.08% of assessed value. Cook County (Chicago) and the collar counties are particularly high.
| County | Effective Rate | Tax on $300K Home |
|---|---|---|
| Cook (Chicago) | 2.10% | $6,300 |
| DuPage | 2.17% | $6,510 |
| Lake | 2.72% | $8,160 |
| Will | 2.52% | $7,560 |
| Kane | 2.76% | $8,280 |
Key Illinois Tax Notes
Calculate Your Illinois Tax
4.95% flat rate makes it simple — see your exact IL tax and take-home pay now.
Open Illinois Tax Calculator →