How to File an IRS Amended Tax Return

An amended tax return is a form filed with the Internal Revenue Service (IRS) to correct mistakes or report omitted information on a previously accepted federal income tax return. Common changes involve adjustments to income, deductions, or credits that alter the final tax liability. This process is different from correcting a return that was rejected by the IRS upon its initial submission.

Deciding Whether to Amend Your Tax Return

An amended return is required for substantive changes, such as correcting your reported income, whether it was under-reported or over-reported. Other common reasons include changing your filing status, for instance from single to head of household, or adjusting the number of dependents claimed. You must also file an amendment to fix errors related to tax deductions and credits that you either failed to claim or claimed incorrectly.

However, not all mistakes require an amendment. The IRS often corrects simple mathematical or clerical errors on its own and will notify you by mail of any changes. If you forgot to attach a form like a W-2, the IRS will usually send a notice requesting the document, which does not require you to file an amended return.

To claim a refund, you must file an amended return within three years from the date you filed your original return or within two years from the date you paid the tax, whichever is later. For returns submitted before the April tax deadline, the three-year period begins on that deadline. Certain circumstances, like a federally declared disaster, may extend this window.

Required Information and Form Completion

Before completing an amended return, you must gather several documents. The primary document is a copy of your original tax return (Form 1040). You will also need any new or corrected informational documents that are prompting the change, such as corrected Wage and Tax Statements (Form W-2), various Forms 1099, or new records that substantiate changes to deductions or credits.

The official form for this process is Form 1040-X, Amended U.S. Individual Income Tax Return. You must use a separate Form 1040-X for each tax year you are amending and clearly indicate the calendar year of the return being corrected.

Form 1040-X uses a three-column format to show the changes being made. Column A is for the figures as they appeared on your original return. Column B is where you will enter the net increase or decrease for each line item you are changing. Column C shows the corrected amount, which is the sum or difference of the figures in Columns A and B. This structure provides a clear comparison for the IRS.

Part III, the “Explanation of Changes,” requires a concise written explanation for each change. For example, you might state that you are “amending to report income from a Form 1099-MISC that was received after the original return was filed.” This narrative helps the IRS understand the reason for the amendment.

How to File an Amended Return

You have two primary methods for filing your completed Form 1040-X: mailing a paper copy or e-filing through tax software. Your filing method may depend on the tax year you are amending.

For those filing by mail, place the completed and signed Form 1040-X on top. Behind it, attach any new or changed tax forms or schedules that are affected by the amendment, such as a corresponding Form 1099 for a new source of income. You must mail the package to the correct IRS processing center, and the specific mailing address can be found on the IRS website.

Electronic filing is an available option for more recent tax years, generally the current year and the two preceding years. Many major tax software programs support the e-filing of Form 1040-X and will transmit the form directly to the IRS.

Tracking and Finalizing Your Amended Return

After you submit Form 1040-X, you can monitor its progress using the “Where’s My Amended Return?” tool on the IRS website. The tool becomes available approximately three weeks after you file. To use it, you will need to provide your Social Security Number, date of birth, and zip code. Processing an amended return generally takes 8 to 12 weeks but can take up to 16 weeks.

The outcome of your amended return will be either a tax refund or an additional tax liability. If you are due a refund for tax years 2021 and later and filed electronically, you can have it sent via direct deposit. If you filed a paper return, you will receive a paper check. It is advised to wait until you have received your original refund before filing an amendment that claims an additional one.

If the amendment results in you owing more tax, you should pay it as soon as possible to minimize potential penalties and interest. You can pay online through the IRS website or mail a check with your paper-filed Form 1040-X. If you file and pay by the original April tax deadline, you can avoid penalties and interest, but if you file after the deadline, the IRS will calculate any interest or penalties owed and send you a bill.