Did you know that you can amend a tax return? If you notice that you made an error on a tax return you already filed, you can (and should) amend your return to make sure you don’t run into trouble with the IRS. If you do need to amend your tax return, there are some things you should know to help you do so correctly. In this post, we’ll cover everything you need to know about amended returns, including when you need to amend, how to amend, what to do if you owe more after amending, amendment deadlines, and what you should do after you amend.

When Do You Need to Amend Your Tax Return?

If you discovered an error on a tax return, you should amend your return in most cases, with the one exception of simple mathematical or clerical errors, which the IRS will correct. For other errors, you should file an amendment yourself. Examples of errors you should amend include incorrect filing status, number of dependents, income, deductions, and credits.

How Do You Amend Your Tax Return?

Unfortunately, you can’t electronically amend your tax return. You have to use a paper form. The form to use is Form 1040X, the Amended U.S. Individual Income Tax Return.

To amend your return, fill out Form 1040X and send it in the mail to the address on the form. You can do this yourself or have your tax preparer fill and send the form for you.

What Do You Do If You Owe More After Amending?

If your amended return shows that you owe more tax to the IRS, you should pay the additional tax as soon as possible to avoid paying more in penalties and fees. If you happen to amend your return before the payment deadline for that tax year, you won’t be subject to any penalties or fees as long as you pay on time.

Is There a Deadline for Amending a Return?

To claim a refund, there is a deadline for filing a Form 1040X. This deadline is within three years of the time of the return’s original filing or within two years of the date you paid the tax (whichever date is later). If you filed the original return early, the return is considered filed on the due date (which is usually April 15th).

What Do I Do After Amending a Return?

After you’ve amended your return, if you have additional tax to pay, do so as soon as possible.

If you want to check the status of your amended return, you can do so on the IRS’s online WMAR (Where’s My Amended Return?) tool. It will take up to 3 weeks to see the initial status of your return on their online tool and up to 16 weeks for the amended return to be fully processed. The IRS asks that you not call them about anything before the 3 week mark unless they’ve sent you a message asking you to call.

On the WMAR tool, there are three processing stages to watch for: Received, Adjusted, and Completed. Once your amended return status is “Completed,” you’ve successfully amended your return.