Prepare An Illinois State Tax Amendment
Made a mistake on your Illinois tax return? No worries! You can amend it for the 2024 tax year using Form IL-1040-X. This is different from the IRS Form 1040X used for federal amendments.
You can prepare an Illinois Tax Amendment Form for the current Tax Year (2024) on eFile.com, however you can not file it electronically, you must mail it in. For all previous IL Tax Years complete form IL 1040-X, see below by Tax Year.
The IRS may notify you of a change needed on your federal return, or you might discover an error yourself. In either case, the IRS will inform the Illinois Tax Agency. To ensure your state return reflects any federal changes, you should file an Illinois Tax Amendment within one year.
Illinois Tax Deadlines, Forms, Extension, Penalties
Prepare only an IL State Return
File a 2024 tax year Illinois Tax Amendment
Only Option:You will need to complete, sign
IL Form IL-1040-X for the appropriate Tax Year- Print, Mail the Form to IL Tax Department to:
Illinois Department of Revenue
P.O. Box 19047
Springfield, IL 62794-9047
IL Tax Amendment Form IL-1040-X
This Form can be used to file a: Tax Amendment, Change of Address.
Step 1: Select the Form IL-1040-X by Tax Year below.
Step 2: Sign, Mail Form IL-1040-X to the address listed above
For all Tax Years prior to the
current tax year Prepare, Print, Sign and Mail-In - see address above - your Tax Amendment by Tax Year as soon as possible.
Illinois Refund Deadlines
A. Three years from the due date of the original tax year return, including valid filing extensions.
B. One year from the final determination of the amended federal return or federal change, whichever is later, provided that the allowable refund is not more than the decrease in Illinois tax attributable to the federal change or correction.
C. Two years from the payment of an assessment, provided the amended return raises issues relating only to the prior assessment and the refund does not exceed the amount of tax paid on the prior assessment.
D. Two years from the filing of an amended Illinois return resulting in the payment of additional tax, provided that the current amended return raises issues relating solely to the prior amended return and that the refund does not exceed the amount of the tax payment made as a result of the prior amended return.
Additional Illinois Tax Income Taxes Deadlines
Will I get a bigger tax refund in 2026?
Good news for taxpayers! Thanks to adjustments to combat rising inflation, the IRS anticipates many will see larger tax refunds for their 2025 taxes (filed in 2026).
Take charge of your finances! This page offers tips for tax planning in the coming year, helping you maximize your potential refund. Utilize our free 2025 Tax Refund Calculator to get a preliminary estimate of your taxes.
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