Everything You Need to Know
About Filing an Amended Tax Return

The U.S. tax code is complicated, even to experts who make a career of understanding it. Making a mistake when you file a tax return is not uncommon. It can happen for a variety of reasons: there’s new information to provide, or newly discovered eligibility for a deduction or credit. No matter the cause, mistakes happen.

The good news is you can fix them. It’s possible to file an amended income tax return and make a correction. The process is fairly easy, it requires you to file IRS Form 1040-X (Amended U.S. Individual Income Tax Return) and submit any corrected or new documents that were not filed with your original return.

When filing an amended return, there are some things you should know. First, there’s usually a three year window to amend your return. It starts from the original filing deadline. So if you made a mistake on your 2017 income taxes, you have until April 2020 to file From 1040-X and amend your return. (Always be sure to verify these and other details on the IRS website, as tax laws and requirements change regularly.)

First decide if it’s even necessary. You may not need to file an amendment with Form 1040-X if the mistake was something simple, like a math error. That’s because the IRS already has a system in place to catch and correct common mistakes.

That said, math errors sometimes do require an amendment. If you’re unsure whether an error warrants filing an amendment, reach out to the IRS directly before you send in new documentation and your 1040-X.

In some cases, such as missing W-2 documentation, the IRS will reach out to you and request those documents. The written request eliminates the need for an amended tax return on the filer’s part. So if this is the case for you, then just wait to be contacted by mail and follow IRS instructions.

Please note the IRS does not contact via phone or email – so be aware of potential scams or ploys to obtain personal information.

When is it Necessary to File an Amended Tax Return?

Now that we’ve considered some of the reasons an amended return may not be necessary, you’re probably wondering when the 1040-X is warranted. Below are some possible scenarios.
Please note this is not an exhaustive list. Rather, these are a few examples of when you might be required to file an amended return.
  • You filed individually, but you are married and want to file jointly.
  • You need to add or remove claims for dependents.
  • There was a change in your income.
  • Documents such as W-2s that were unavailable when you first filed.
  • Additional income that should have been reported.
  • Claiming the student loan interest deduction or other eligible expenses.
  • Newly discovered eligibility for deductions, credits, or exemptions.
  • Reporting additional income, such as from a personal business.
  • This is a common mistake: taxpayers may learn that certain items or assets they own are taxable.
  • Discovering new deductions, credits, exemptions, etc.
To navigate the amendment process, it helps to know where the mistake occurred (or what needs to be changed). This will help when you’re filling out the 1040-X.
When an amended return is necessary, these are the steps you should follow. Before beginning the process, though, review this list of things to keep in mind.
Please note the following before proceeding:
(Click to expand each item and find more information.)

If you haven’t submitted your original return yet, simply fix it before you file. But if your return has already been filed, wait until it’s been processed by the IRS.

You can use online preparation services to help prepare your amended filing, but ultimately the hard copy has to be mailed in. Consider using certified mail, to ensure it arrives in a timely fashion. Receipt is verified with a signature upon arrival.

This is important to claim any additional refunds. While waiting for additional monies, you are allowed to spend the original refund amount.

This varies by state, so check rules and policies for your individual location.

Line item information should come from the year you are amending, not necessarily the current year. Instructions change from year to year, and some things may not be applicable depending on the year being amended. This includes numbers used for exemptions, credits, and deductions.

For example, the line for health care would be blank in tax returns from 2013 or prior. For 2014, it would be 1040 Line 61, 1040A Line 38, or 1040EZ line 11.

Same as above. Numbers change from year to year, so make sure you’ve got the right worksheet for deductions and exemptions.

Step 1: Gather All the Pieces

Before jumping into the 1040-X, get all of your paperwork together. This includes the original return and any new documentation that needs to be sent in. These are valuable reference materials when filing an amended return. For one thing, looking at your original return can help you pinpoint where mistakes occurred.

When claiming a new deduction or credit, have that documentation on hand. Certain refundable credits are determined based on tax schedules. The 1040-X indicates what these forms or schedules are, and you’ll want to have those as well. If you’re providing a new W-2 that was not previously available, have this on hand.

(If a missing W-2 is the case, look into filing Form 4852 and have a W-2 replacement issued from the IRS. The employer will have to verify the information and a replacement W-2 can be provided.)

There are a few different ways to go about amending a return. If physical copies of previous tax year information are not available, use the IRS database. Previous tax forms are stored here. Remember, while tax software or a paid preparer can help file an amendment, at the end everything must be printed and mailed.

While it’s good to have all of your documentation on hand, the amendment process focuses on the affected areas. Meaning you probably don’t have to submit entirely new forms for your whole tax return. Only the necessary ones.

Depending on the changes, you may have to submit additional forms. The IRS created an instruction guide (link below) to help you determine if additional forms are necessary. An example of this is a case where you’re amending to claim an Earned Income Credit (EIC) and have a qualifying child. In this instance, Schedule EIC (1040) or Schedule EIC (1040A) would need to be included.

Step 2: Have the Forms Ready

To file an amended tax return, you’ll certainly need the IRS form itself (found here – PDF link). The 1040-X Amended U.S. Individual Income Tax Return form has three columns and three parts. The top section is basic personal information and should match the original tax return.

The next part has the three columns. Column A is used to provide the amounts from the original tax return. Column C is to input the correct figures. In Column B, indicate the “net change” between Column A and C.

For example, if the tax return indicated $1000 in income but needs to reflect an additional $2000 in income, it would look like this:

If reflecting a decrease in income or other numbers, the columns would look like this:

These are simple examples meant to provide an example of what each column might look like.

Part I of the form is used to document and changes in exemptions or claims to new exemptions. This is where to claim new dependents, release claim to dependents, and more. Part II is asking for a donation to the Presidential Campaign Fund.

The second page of the form, or Part III, is used to explain the changes and why you are filing for an amendment. Greater detail in this section allows for faster processing, so be sure to provide clear and complete information. This is where you explain the “why” behind the previously provided information. Consider having a friend or family member read over this section to provide feedback on the clarity of your explanation. This can help ensure the IRS receives all the information needed to process your amendment. The IRS has also provided an extensive instruction guide that can assist in filing the Form 1040-X.

Depending on the type of change, you may not need to fill out all the columns. Lines applicable to different scenarios include:

  • Change in filing status: Lines 1-23 of 1040-X
  • Exemptions: Lines 1-30
  • Income or Adjustments to Income: Lines 1-23
  • Itemized or standardized deductions: Lines 1-23
  • Tax before credits: Lines 5-23
  • Nonrefundable credits: Lines 6-23
  • Other taxes: Lines 6-23
  • Payment and refundable credits: Lines 10-23

If you’re not sure what information needs to be amended, refer to the original tax return. The line with the mistake should fall under one of the bullet points above.

On the 1040-X amendment form, list all dependents claimed on original return as well as any new dependents. If amending to remove dependents from the original tax return, do not list them in the dependent section of the 1040X.

Step 3: Signed, Sealed, Delivered, Processed

As mentioned before, an amendment has to be physically mailed in. After double checking that all forms and supporting documents are ready to go, send all pertinent information to the IRS. If the amendment results in taxes owed, include the additional tax payment. This minimizes interest and penalties if the payment is technically late. It can take the IRS 8 to 12 weeks to process an amendment.

At the top of Form 1040-X, note the tax year being amended. The 1040-X must be filled out separately for each tax year being amended. If amending multiple years, mail each year in an individual envelope. In this envelope, include the copy of the tax return that is being amended.

Step 4: Wait and Confirm

It’s possible to check the status of Form 1040-X for the most recent year and up to three previous years. It can take up to three weeks to populate the amendment information in the IRS system. To check the status, you need your Social Security Number, date of birth, and zip code used when filing. To track the Amended Return, use the IRS Where’s My Amended Return tracking feature. The tool is online and also available by phone at (866) 464-2050.

Keep a Record of Your Amendments
When everything is printed and mailed to the IRS, keep records of the amendment with the rest of your income tax information. It can be handy to reference in future filing periods.
You may need to provide a copy of the completed 1040-X at some point. So it’s good practice to keep tax returns, amended returns, W-2s, and all other federal and state tax documents. While the IRS does have a database with federal tax returns, it only retains copies for a certain length time. In the end, it is your tax information and therefore your responsibility to accurately maintain records and personal documentation.
For more information on Form 1040X Amended Tax Return, refer to the official IRS website or contact the IRS directly. Policies and laws may change over time and this page will be updated to reflect pertinent changes. For the most up-to-date policies, contact the IRS. The information outlined here is based on the 2018 Amended U.S. Individual Income Tax Return Form that was last revised in January 2018.