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What is Form 1040X?

Diane Goettel
Diane Goettel
Diane Goettel
Diane Goettel

In the United States tax system, form 1040x is used when individuals need to make corrections or amendments to federal tax returns that they have already filed. A person may use form 1040x after realizing that she forgot to report a small amount of income that she received for a project that she completed early in the year, which would be an income that was additional to her regular bi-weekly paycheck. In another instance, a person might use form 1040x to report a charitable donation that he made and then forgot about when he was filing his taxes. Depending on the kind of amendments that are being made, a person who files form 1040x may have to pay additional taxes or may actually be eligible for a larger tax return than they had originally calculated.

People who file their taxes on their own can obtain form 1040x from the United States Internal Revenue Service (IRS) website. The form comes with instructions for completion, as well as instructions for how and where to send the form. The complexity of the information that is provided on this form is directly related to the complexity of one's taxes. Despite the complexity of these calculations, there are a few key pieces of information that should be included on form 1040x. In short, the form is used to present the amount of income that was originally reported, the recalculated amount of income, and the reason for the amendment.

Corrections to an already filed Form 1040 can be made using Form 1040X.
Corrections to an already filed Form 1040 can be made using Form 1040X.

It is important to file form 1040x as soon as a mistake is caught. There are a number of reasons for this. One is that the Internal Revenue Service will likely catch the oversights. In addition to collecting on owed taxes, the IRS will also probably calculate interest on the owed taxes and add that on to the full amount. By filing this form as quickly as possible and making the correct payments, it may be possible to avoid paying interest.

Mistakes made to a 1040 filed online can be corrected online by filing a 1040x.
Mistakes made to a 1040 filed online can be corrected online by filing a 1040x.

Those who are filing form 1040x may also have to amend their state tax returns. The form 1040x only allows applies to federal tax returns. For information on how to file an amended state tax return, contact the state tax agency. The IRS website has links to the state government sites, so it is a good place to start when beginning this process.

Diane Goettel
Diane Goettel

In addition to her work as a freelance writer for WiseGEEK, Diane is the executive editor of Black Lawrence Press, an independent publishing company based in upstate New York. She has also edited several anthologies, the e-newsletter Sapling, and The Adirondack Review. Diane has a B.A. from Sarah Lawrence College and an M.A. from Brooklyn College.

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Diane Goettel
Diane Goettel

In addition to her work as a freelance writer for WiseGEEK, Diane is the executive editor of Black Lawrence Press, an independent publishing company based in upstate New York. She has also edited several anthologies, the e-newsletter Sapling, and The Adirondack Review. Diane has a B.A. from Sarah Lawrence College and an M.A. from Brooklyn College.

Learn more...

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    • Corrections to an already filed Form 1040 can be made using Form 1040X.
      By: cphoto
      Corrections to an already filed Form 1040 can be made using Form 1040X.
    • Mistakes made to a 1040 filed online can be corrected online by filing a 1040x.
      By: steheap
      Mistakes made to a 1040 filed online can be corrected online by filing a 1040x.