It can happen to the best of us. You think you're all done with your taxes, and just as you're congratulating yourself on getting them done early, you get a tax form in the mail with information you should have included on your return. Or you're flipping through your return and notice a mistake. All of these errors and more can be corrected simply by filing an amended tax return using Form 1040-X.[1] Don't use this form to correct typos or mathematical errors — the IRS will fix those for you. You only need to file a 1040-X to make changes to your filing status, income, deductions, or credits.[2]

Method 1
Method 1 of 2:

Completing the Form

  1. 1
    Get a copy of the original tax return that you want to amend. You'll need at least one copy of the tax return you want to amend so you can copy the original numbers from that form onto your Form 1040-X. You can work with a digital copy, but it might be easier if you print it out so you can mark on it.[3]
    • If you originally filed your taxes using an online service, you can usually download copies of previous years' returns from your account.
    • If you don't have a copy of the tax return you want to amend, go to https://www.irs.gov/individuals/get-transcript and get a transcript. Choose the "Tax Return Transcript" for the type, which provides all the information you need to fill out the 1040-X.[4]
  2. 2
    Download Form 1040-X from the IRS website. Go to https://www.irs.gov/forms-pubs/about-form-1040x to download Form 1040-X and its instructions. The instructions might seem rather complicated, but try to read through them as best you can before you start filling out the form.[5]
    • The instructions go through a lot of special circumstances and reasons for amending a return. Don't worry about reading anything that doesn't apply to your situation.[6]
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  3. 3
    Search the IRS website for tax forms for the original return. In the upper right-hand corner of the IRS homepage, you'll see a search box. Type in the words "tax forms for" followed by the year of the original return you want to amend. You'll get all the forms that were valid for that year.[7]
    • To fill out the 1040-X, you'll need a blank copy of the tax return you completed and the instructions for filling out that form.
  4. 4
    Complete the blank return with the amended information. On the blank return that matches the year of the original return, copy the correct information from your original return. Then, fill in the correct information for the lines that you wanted to change.[8]
    • Keep in mind that information you amend will likely cause further changes. For example, if your employer sent you an amended W-2, a change in your income would change your adjusted gross income and your tax liability.
    • When you've completed the blank return, make a clean copy for the IRS and write "Amended Return" at the top of it. Use the other copy as your work copy. Mark or highlight the numbers you changed on your work copy so you can easily find and transfer the information to Form 1040-X.
  5. 5
    Fill in your personal information on Form 1040-X. At the very top of Form 1040-X, check the box next to the year of the tax return you're amending. If the year isn't provided, write it in next to "Other year." Then, fill out your name, address, and Social Security number.[9]
    • If you're married, include your spouse's name and Social Security number as well.
  6. 6
    Choose a filing status. This is the one part of the form that you have to fill out even if you're not changing anything. You have to check one box for your filing status. If you're not changing your filing status as part of your amendments, check the same box you checked on your original return.[10]
    • You can check a different box if you want to change your filing status. You'll explain this in writing in a different part of the form.
    • If you are married and originally filed a joint return, you can't change to "married filing separately" after the due date for the original return.
  7. 7
    Find the lines that correspond to the information you need to change. Each line on the 1040-X relates to a specific line on your original tax form. The numbers of the lines may vary depending on the year of the return you want to amend, but the description of the information on the line will be the same.[11]
    • If you highlighted the changes on your amended return
    • If you mark the lines you need to use on the 1040-X, you don't have to worry about inadvertently leaving something off.
  8. 8
    Enter your information in all 3 columns only for amended items. Go to your original return and write down the value you provided for the items you need to change in Column A of the appropriate line on Form 1040-X. Then, look at your amended return and write the amended value in Column C.[12]
    • In Column B, write the difference between Column A and Column B. If the amended value is lower than the original value, put a negative sign ( - ) in front of the number.
    • For example, if you originally reported $18,000 in income, then got an amended W-2 from your employer showing that your income was actually $18,250, you would put $18,000 in Column A, $250 in Column B, and $18,250 in Column C.
  9. 9
    Explain the changes you made in Part III of Form 1040-X. Write a brief description of the changes that you made. If you made multiple changes, write a separate explanation for each change. If you have any tax documents that relate to those changes, attach them to the form.[13]
    • For example, if you amended your income because you got an amended W-2 from your employer, you might write: "Amended income to reflect amended W-2 received after I had already filed my return." Then, you would attach a copy of that amended W-2 to the form.
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Method 2
Method 2 of 2:

Submitting the Form

  1. 1
    Attach your supporting documents to the front of Form 1040-X. In the upper-right corner of each form you're attaching, you'll see the phrase "Attachment Sequence No." followed by a number. Order your amended tax return and other documents with the numbers in order.[14]
    • If the changes you made also required you to make changes to other schedules, arrange those schedules in order behind the form they relate to. For example, if you have an amended return and schedules related to the original return, you would order the schedules behind the amended return.
    • You only need schedules that have changed information. If you had schedules with your original return but nothing on them changed, you don't need to include them with your Form 1040-X.
    • You usually don't need to include a copy of your original return, unless you're amending your return in response to a letter from the IRS and the letter told you to include a copy of your original return. You don't need to include a copy of the letter.
  2. 2
    Mail the form and attachments to the appropriate address. As of 2020, you cannot file form 1040-X online. Instead, there are 5 different addresses listed in the instructions for Form 1040-X. The address you use depends on where you live.[15]
  3. 3
    Check the status of your return online after 3 weeks. It takes at least 3 weeks from the date you mailed your amended return for it to show up in the IRS system. After that, get updates at https://www.irs.gov/filing/wheres-my-amended-return. Enter your Social Security number, date of birth, and ZIP code to check your return's status.[17]
    • You can also check the status of your return by calling 866-464-2050. It's an automated line, you just enter your information the same as you would online.
    • Keep in mind that it can take up to 16 weeks for the IRS to process an amended return.
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Glossary of Tax Terms for US 1040X Tax Returns

Expert Q&A
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  • Question
    What is the difference between a 1040 and 1040x tax form?
    Alan Mehdiani, CPA
    Alan Mehdiani, CPA
    Certified Public Accountant
    Alan Mehdiani is a certified public accountant and the CEO of Mehdiani Financial Management, based in the Los Angeles, California metro area. With over 15 years of experience in financial and wealth management, Alan has experience in accounting and taxation, business formation, financial planning and investments, and real estate and business sales. Alan holds a BA in Business Economics and Accounting from the University of California, Los Angeles.
    Alan Mehdiani, CPA
    Certified Public Accountant
    Expert Answer
  • Question
    What do I do if I need to change my 1040 tax form?
    Alan Mehdiani, CPA
    Alan Mehdiani, CPA
    Certified Public Accountant
    Alan Mehdiani is a certified public accountant and the CEO of Mehdiani Financial Management, based in the Los Angeles, California metro area. With over 15 years of experience in financial and wealth management, Alan has experience in accounting and taxation, business formation, financial planning and investments, and real estate and business sales. Alan holds a BA in Business Economics and Accounting from the University of California, Los Angeles.
    Alan Mehdiani, CPA
    Certified Public Accountant
    Expert Answer

    Support wikiHow by unlocking this expert answer.

    The best thing to do would be to file a 1040-X form. This will allow you to amend your original 1040.
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Warnings

  • This article is accurate as of July 2020. Procedures may differ in later tax years.
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  • If you completed paper tax returns by hand, you don't need a 1040-X to correct mathematical errors. The IRS will correct these for you automatically.[20]
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  • If you need to file a 1040-X, you must do so within 3 years after the original return was filed or within 2 years after the tax was paid, whichever is later.[21]
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About This Article

Alan Mehdiani, CPA
Co-authored by:
Certified Public Accountant
This article was co-authored by Alan Mehdiani, CPA and by wikiHow staff writer, Jennifer Mueller, JD. Alan Mehdiani is a certified public accountant and the CEO of Mehdiani Financial Management, based in the Los Angeles, California metro area. With over 15 years of experience in financial and wealth management, Alan has experience in accounting and taxation, business formation, financial planning and investments, and real estate and business sales. Alan holds a BA in Business Economics and Accounting from the University of California, Los Angeles. This article has been viewed 164,959 times.
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Co-authors: 15
Updated: February 16, 2023
Views: 164,959
Categories: Taxes
Article SummaryX

If you forgot to include information on your tax return or filled in the wrong information by mistake, you can file an amended tax return using Form 1040-X. You'll need a copy of the original tax return you want to amend, along with a blank copy of the tax return for that year. You can find a copy of both on the IRS website. Once you have the documents you need, fill out the blank return with your amended information. Then, fill out Form 1040-X. For each item you want to amend, write down the value you provided on your original tax return in column A and the new value you want to amend it to in column C. Put the net difference between the two values in column B. Finally, explain the changes you're making under part three of the form. To learn the correct way to submit your Form 1040-X, check out the full article below!

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