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.
Will IL tax my Roth conversions?
Conversions are taxable federally and typically flow to IL; IL retirement exclusion usually applies to distributions, not conversions—check IL guidance.
How do I amend my Illinois return?
File Form IL-1040-X after your original IL-1040 is processed; include revised schedules (e.g., Schedule ICR/CR/M) and explanations.
Why does Illinois distinguish pre-1969 and post-1969 gains?
Because Illinois enacted its income tax on August 1, 1969, any appreciation before that date occurred before the state had authority to tax income. Form IL-F preserves fairness by taxing only the gain realized since Illinois income tax law took effect. This approach avoids retroactive taxation while ensuring current gains are taxed appropriately.
When should Schedule FD be filed?
File Schedule FD with your annual IL-1040 return for the tax year in which the deferred income became federally taxable.
Why is Schedule M important for accurate Illinois taxes?
Illinois uses Schedule M to ensure fairness in applying its flat 4.95% tax rate. Because Illinois starts from federal AGI, this form ensures only Illinois-approved income is taxed and proper deductions are applied. It’s especially vital for retirees, military personnel, and taxpayers with multistate investments.
Important Notes
All calculations are estimates for guidance only. Always review your return and consider professional advice when submitting official filings.