2025 Illinois Form 1040

What Is Illinois Form IL-1040?

Illinois Form IL-1040 is used by full-year residents, part-year residents, and nonresidents to file their state income tax return. The purpose of Form IL-1040 is to determine your tax liability for the state of Illinois. Nonresident and part-year resident filers are also required to complete Illinois Schedule NR.

The State of Illinois does not have an Easy Form (EZ) or Short Form. Read the General Information section of the IL-1040 instructions book to help determine if you should file as a full-year resident, part-year resident, or nonresident for tax year 2025.

Who Must File Illinois Form IL-1040?

You must file an Illinois tax return if you were required to file a federal income tax return. There is also an income test for those who were not required to file a federal income tax return. You must file an Illinois tax return if your Base Income (line 9) exceeds your total Exemptions claimed (line 10). For tax year 2025, Single residents under the age of 65 must file if their income is more than $2,850. Married residents with no dependents must file if their income is more than $5,700.

Even if your Base Income is below the amount specified for the total exemptions claimed, you may still want to file an Illinois tax return. You may receive a refund for the state tax amount shown on your Illinois W-2, for example. You may also be eligible for any Illinois earned income credit or other low-income related credits.

Read the Who Must File section of the IL-1040 instructions book to help determine if you should file a state income tax return for tax year 2025.

Printable Illinois State Tax Forms

Printable Illinois Form IL-1040 Instructions

Click any of the Illinois income tax forms and instructions links above to download, save, view, and print the file for the corresponding year. These free PDF files are unaltered and are sourced directly from the publisher.

How To Check The Status Of My Illinois Tax Return?

To check the status of your Illinois income tax refund online, visit the Illinois Department of Revenue website and use their Where's My Refund service. Illinois Department of Revenue refund processing time is stated as within three weeks for an electronically filed return and as long as 15 weeks for a mailed in paper return.

To check the status of your Illinois income tax refund for 2025 you will need the following information:

• Name(s)
• Address
• Social Security Number
• Adjusted Gross Income (Line 1)

The requested information must match what was submitted on your 2025 Illinois Form IL-1040. To check prior year refunds, you will need to contact the Illinois Department of Revenue service center by phone or mail.

To contact the Illinois Department of Revenue service center by phone or email, use the check your refund status link above. Alternatively, read or print the 2025 Illinois Form IL-1040 instructions to obtain the proper phone number and mailing address.

Frequently Asked Questions (FAQ)

Here are answers to some of the most common questions about Illinois Form IL-1040. These FAQ can help clarify how to fill out, document, and submit Form IL-1040 correctly.

Who must file Illinois Form IL-1040?

Illinois residents generally must file Form IL-1040 if they were required to file a federal income tax return or if their Illinois base income exceeds their exemption allowance. Nonresidents and part-year residents may also need to file when they have Illinois-source income.

What filing status should I use on Form IL-1040?

In most cases, your Illinois filing status matches your federal filing status. Review the Illinois instructions for exceptions, including the state treatment of a federal qualifying surviving spouse and certain injured-spouse situations.

When is Illinois Form IL-1040 due?

For tax year 2025, Form IL-1040 is generally due April 15, 2026. An extension provides more time to file, but any tax due should be paid by the original deadline.

Can I amend an Illinois Form IL-1040?

Yes. Use Form IL-1040-X to amend a previously filed Illinois individual income tax return. Include any schedules or documentation needed to support the changes.

What do I need before filing Illinois Form IL-1040 online?

Have your completed federal return, wage and income statements, and identification information ready before filing online. You may also need records for credits you intend to claim and bank-account information for direct deposit or payment.

Can I file Illinois Form IL-1040 electronically?

Yes, IL Form IL-1040 can be filed electronically as part of your overall Illinois tax return. If you're using income tax software, the program will prompt you to complete IL Form IL-1040 if your tax situation requires it.

Last updated: July 15, 2026

State Tax Forms