Illinois Tax Calculator
The Illinois (IL) Tax Calculator is updated for the 2026/27 tax year. Illinois applies a flat-rate state income tax. This tool estimates your Illinois state tax alongside federal income tax, Social Security, and Medicare to show projected take-home pay.
Quick Access Tools
Quick Illinois Tax Calculator
Enter income and filing status, then select Calculate for instant results. Use tabs to add itemized deductions, dependents, retirement deferrals, and withholdings. Illinois has no local wage income tax; leave Local Taxes off unless modeling a custom scenario.
Input key: F Used in Federal tax calculations S Used in State tax calculations
How to Calculate Income Tax in Illinois for 2026/27
- Enter your gross annual income and any adjustments.
- Choose your filing status (Single, Married filing jointly, etc.).
- Click Calculate to view Illinois state tax, federal taxes, FICA/Medicare, and take-home pay.
Advanced Options
- Compare itemized deductions with the federal standard deduction.
- Model IRA/401(k) deferrals and other pre-tax benefits.
- Add dependents to reflect child-related credits.
- Enter withholdings (federal, state, Medicare, Social Security) to project refund or balance due.
Related Calculators
Common Illinois Forms & Schedules
Browse the essential Illinois (IL) tax forms used for personal and business income tax filing. Common examples include Form IL-1040 (Individual Income Tax Return) and Schedule M (Other Additions and Subtractions), along with credits, withholding, and estimated payment schedules supporting Illinois taxpayers.
- Illinois Form IL 1040 Individual Income Tax Return
- Illinois Form IL 1040 Schedule G Voluntary Charitable Donations
- Illinois Form IL 1040 Schedule M Additions and Subtractions
- Illinois Form IL 1040 Schedule NR Nonresident and Part-Year Resident
- Illinois Form IL 1040 Schedule ICR Illinois Credits
- Illinois Form IL 1040 Schedule CR Credit for Tax Paid to Other States
- Illinois Form IL 1040 Schedule IL E EITC Earned Income Credit
- Illinois Form IL 1040 X Amended Individual Income Tax Return
- Illinois Form IL 1040 Schedule 1299 A Tax Subtraction and Credit Summary
- Illinois Form IL 4562 Depreciation and Amortization Adjustments
- Illinois Form IL 1299 C Tax Credit Recapture Schedule
Additional Resources
- All State Calculators
- Federal and State Tax Tables
- Federal Income Tax Calculator
- Report an issue or request a correction
Frequently Asked Questions
Quick answers for Illinois filers: flat-rate state tax, federal coordination, deductions, dependents, and withholdings.
Do I need to file IL-1040-X if the IRS changes my income?
Yes. If the IRS adjusts your federal return and it affects Illinois tax, you must file IL-1040-X within 120 days of receiving the federal notice.
Are donations made through Schedule G-L tax-deductible?
Yes. Your Schedule G-L donations are eligible for a federal charitable deduction if you itemize on your federal Form 1040 Schedule A. Keep a copy of the filed schedule and any Lottery confirmation of your gift. The contribution will increase your Illinois payment or reduce your refund, but may lower your federal taxable income in the following year.
Changing jobs mid-year in IL
Update income/withholding and frequency; brackets are flat but credits/exemptions still matter.
Who must file Schedule FD?
You must file Schedule FD if you are a former Illinois resident who receives income (such as installment sale gains or deferred bonuses) sourced from Illinois that became taxable for federal purposes during 2026.
What documentation must accompany Schedule 1299-DA?
Attach copies of the other states’ filed tax returns, W-2s, or K-1s showing withholding and payments. Failure to attach proof can lead to denial of the credit. For convenience, you can track and upload copies directly through the MyTax Illinois portal.
Important Notes
All calculations are estimates for guidance only. Always review your return and consider professional advice when submitting official filings.