What is the Illinois state income tax rate?

Illinois uses a single flat rate of 4.95% on net income for all individual filers, regardless of how much you earn. There are no graduated brackets, which makes Illinois tax simple to estimate.

What is the Illinois personal exemption allowance?

For 2024 tax year the Illinois personal exemption allowance is $2,775 per person. You claim one for yourself, one for a spouse on a joint return, and one for each dependent. The allowance is subtracted from income before the 4.95% rate is applied.

Is Illinois income tax really flat?

Yes. A 2020 ballot measure to introduce graduated rates failed, so Illinois retains a constitutionally required flat tax. Everyone pays the same 4.95% marginal and effective rate on net income after exemptions.

Does this include local Illinois taxes?

Illinois has no local or municipal income taxes, so the 4.95% state rate is the only income tax on your wages. Cities like Chicago do not levy a separate income tax.

Is my income data sent anywhere?

No. The calculation runs entirely in your browser. Nothing you enter is uploaded or stored.

Illinois State Income Tax Calculator

Illinois taxes individual income at a single flat rate of 4.95%. There are no brackets and no local income taxes, so estimating your Illinois tax is straightforward once you account for the personal exemption allowance. This free calculator does both.

How it works

The Illinois individual income tax formula is:

Start from your net income (federal AGI with Illinois additions/subtractions; for most wage earners, AGI is a close approximation).
Subtract the personal exemption allowance — $2,775 per exemption for the 2024 tax year. Count yourself, your spouse on a joint return, and each dependent.
Apply the flat 4.95% rate to the remaining net income.

Because the rate is flat, your effective rate is always slightly below 4.95% — the exemption pulls it down a little.

Example

A married couple filing jointly with $90,000 net income and two children claims 4 exemptions: 4 × $2,775 = $11,100. Net taxable income is $78,900, and 4.95% × $78,900 = $3,905 of Illinois state income tax. The effective rate is about 4.3%.

Notes

This estimate covers state income tax only — not FICA, federal income tax, or property tax. Illinois additions and subtractions (such as federally taxed retirement income, which Illinois excludes) can change your net income; this tool uses your entered figure directly. Exemption amounts are inflation-adjusted annually.