TAX SEASON 2024

What should you do if you made a mistake filing your taxes? What is Form 1040-X?

If you discover that some of the information on your tax return is inaccurate, you will have to file an amended form before the tax deadline.

Keith SrakocicAP

Personal tax returns are filed using Form 1040, however, if you have made a mistake filling in your tax return, or have changed address, you still have time to file an amended tax return – you will need to fill out another, two-page document: Form 1040-X, which is available here.

Amended tax returns are accepted by the IRS up to a three years after your original tax return was filed – that means that this year, the IRS will accept amended tax returns for the years 20212022 and 2023.

There are no penalties or interest charged if you submit your amended tax return before the deadline day, which this year is 15 April. If your return shows that you owe tax, any amended tax returns received after that date will be charged interest on a daily basis – until the balance is paid in full. You usually have 21 calendar days, from the day of notice to pay any additional tax.

Amended tax returns cannot be filed online. Form 1040-X has to be printed off, filled in manually with black pen and mailed directly to the IRS. Depending on which state you live in, the addresses to which you must send Form 1040-X to can be found here.

To complete Form 1040-X, you will need:

  • Form 1040-X;
  • A copy of the return you are amending (for example, 2016 Form 1040), including supporting forms, schedules, and any worksheets you completed;
  • Notices from the IRS on any adjustments to that return
  • Instructions for the return you are amending. If you don't have the instructions, you can find them online at IRS.gov/Forms. If you are amending a prior year return, click on the link for prior year instructions under "Other Options." You can also order paper copies of the instructions for your return at IRS.gov/OrderForms or by calling 800-829-3676.

The IRS has published a list of FAQs.

How to complete form 1040-X

Form 1040-X used to file an amended tax return is very similar to Form 1040. You will need to tick the relevant box for the year of your declaration at the top of the form (2021, 2022 or 2023) and fill in all of the sections as you would for a normal tax return.

The entries you make on Form 1040-X under the column headings Correct amount and Correct number or amount are the entries you would have made on your original return had it been done correctly.

On Form 1040-X, you will also have to fill out Part III, giving an explanation of the changes you have made to your tax return, and why you are filing an amended tax return. All relevant supporting documents, new or changed forms must also be attached behind Form 1040-X. Don’t attach a copy of your original return, correspondence, or other items unless you are required to do so.

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