Amending My Return

Note: If the federal change results in a refund, do not file Form IL-1040-X until you receive notification that your change has been accepted by the IRS.

For more information, see Form IL-1040-X and instructions.

Questions and Answers

What is the difference between a federal and state change when filing Form IL-1040-X?

A federal change is anything that pertains to your federal filing status, adjusted gross income, exemption allowance, and earned income credit. A state change is when you are not required to file a federal Form 1040-X, Amended U.S. Income Tax Return. An example is an error is made in calculation of credit, such as the property tax credit or the education expense credit. Another example is if you failed to claim a subtraction on your Form IL-1040 for retirement income shown on lines 4b, 5b, and 6b of your original federal Form 1040, Page 1.

How long do I have to file an amended individual income tax return?

For a state change

If your change decreases the tax due to Illinois and you want a refund, you must file Form IL-1040-X, Amended Individual Income Tax Return, within

• three years after the extended due date, 
• three years after the date your original return was filed, or 
•  one year after the date your Illinois tax was paid, whichever is latest.

Note:  The refund allowed on a claim filed within three years after the original return was filed is limited to the total of all payments made within three years and six months prior to the filing of the refund claim. If your change increases the tax you owe to Illinois, you should file a Form IL-1040-X and pay the tax, penalty, and interest as soon as you realize that it is owed.

For a federal change

If your federal change resulted in an overpayment or if you claimed a net operating loss (NOL) carryback, you should not file Form IL-1040-X until you receive a federal finalization notification from the IRS stating that they have accepted your change either by paying a refund or by final assessment, agreement, or judgment. If your federal change increases your Illinois tax, you must file a Form IL-1040-X, Amended Individual Income Tax Return and pay any additional tax within 120 days of the federal finalization date, or you may be assessed a late-payment penalty.

How long does it take to process an amended individual income tax return?

Processing time for an amended individual income tax return varies. IDOR processes these returns in the order they are received. If you are unsure of the status of your return and would like to follow up with us, we recommend that you allow at least 6 months from the date you submitted your amended return before contacting us.

How do I correct an error on my electronically filed Form IL-1040 return?

You may file electronically with an approved vendor or file a paper Form IL-1040-X, Amended Individual Income Tax Return to correct any errors on your electronically filed Form IL-1040 return.

If you are filing Form IL-1040-X due to a federal change, do not file until you receive notification from the IRS showing it was accepted. For more information, refer to the Form IL-1040-X Instructions.

I made a voluntary charitable donation on my Form IL-1040. Can I change this amount on Form IL-1040-X?

No, you cannot change these amounts on your amended return.

Can I file Form IL-1040-X if I have not received my refund from my federal amended return?

No. You should not file your Form IL-1040-X until you receive a federal finalization notification from the IRS stating that they have accepted your change either by paying a refund or by final assessment, agreement, or judgment.

How far back can I file an amended return to claim an overpayment based on changes to my federal return? 

If your federal change decreases your Illinois tax and you want a refund, you must file an amended return (claim for refund) within two years plus 120 days of federal finalization.

If my Illinois tax increases as a result of my federal change, how long do I have to amend and pay the additional liability?

If your federal change increases your Illinois tax, you must file Form IL-1040-X and pay any additional tax within 120 days of the federal finalization date or you may be assessed a late-payment penalty.

How far back can I file an amended return to claim a refund based on a state change only?

If your change decreases the tax due to Illinois and you want a refund, you must file an amended return (claim for overpayment) within three years after the extended due date, three years after the date your original return was filed, or one year after the date your Illinois tax was paid, whichever is latest.

Note: The refund allowed on a claim filed within three years after the original return was filed is limited to the total of all payments made within three years and six months prior to the filing of the refund claim. If your change increases the tax you owe to Illinois, you should file a Form IL-1040-X and pay the tax, penalty, and interest as soon as you realize that it is owed.

What other types of documentation can I provide to show the IRS accepted my amended return?

If you do not have a copy of your federal finalization, call the IRS or go to their website at www.irs.gov to request a tax account transcript.

I have not received my refund, should I include it on my IL-1040-X?

Yes. You must:

• Include all previous overpayments, refunds, and credit carryforward (even if you have not received it) from your original Illinois Income Tax return, previously filed Form IL-1040-X, or for any other reason. Do not include interest that you have received.
• Include your original voluntary contributions to state funds. You may not change the amount of your voluntary contributions to state funds made on your original Illinois Income Tax return.
• Include use tax reported on your original Form IL-1040.