Amending Federal Tax Returns with Form 1040X

| October 6, 2011

If you file your federal tax returns and later realize you made a mistake on your returns, there is the possibility you might have to file an amended tax return using IRS Form 1040X.

Not all tax return mistakes require the amended tax return form 1040 X. Mistakes like mathematical miscalculations or forgetting to attach the appropriate schedules schedule is not a large enough mistake to require using the amendment form form. The IRS easily handles arithmetic errors and missing forms.

When to Use Federal Tax Form 1040 X

You only need to use the form if there were major changes such as:

  • An incorrect filing status
  • Change to income
  • A change in deductions
  • Incorrect credits taken

The 1040 X form is called the amended US individual income tax return. Therefore, it can only be used on individual, not corporate tax returns. It is used to correct returns filed using tax forms 1040, 1040EZ, 1040 A, 1040 NR and 1040 NR-EZ.1040X Columns

Completing form 1040 X is rather self-explanatory. If you look at the form you’ll notice that each line item has three columns. In column A entitled “Original Amount,” insert the figures used on your originally filed tax form.

Now skipping to Column C, entitled “Correct amount,” take the figures from your corrected tax form and insert them in this column.

Lastly, insert the “Net change” in column B. Column B lists the difference between columns A and column B. It’s sort of a checks and balances column. If the sum total of Column A and Column B don’t equal the number listed in column C, you know you’ve got to re-visit your numbers.

What to Attach to Form 1040X

When filing Form 1040X only attach those forms or schedules that have changed. If you received an amended W-2 or had to revise your schedule C only attach the amended W-2 or the revised schedule. It is not necessary to include the entire original tax return and it’s original documentation. Doing so will only confuse matters.

Form 1040X is processed manually and therefore cannot be submitted to the IRS electronically. Sending too many unnecessary documents will do nothing but delay processing. Do yourself a favor and only send the pertinent information.

Filing Deadline for Tax Form 1040X1040X

If you noticed that you made an error in your tax returns the knee-jerk reaction is to file an amended 1040 X as soon as possible. That’s not the way the government wants you to handle it. If you made an error and you are due a larger tax return than originally filed, wait until you receive your refund (even though incorrect) before filing the amended return.

If after filing your taxes you realize you actually owe more than indicated on your original return, you have until the following tax year deadline of April 15 to submit the additional monies due without incurring late payment penalties or interest. The key here is to make sure you pay it by the next years tax deadline. One day beyond the deadline and you start accruing interest and penalties.

Amending Several Tax Years

If you found that you have made several errors over the past few years, complete a separate 1040X form for each year and mail them in separate envelopes. As mentioned earlier, they are hand processed one tax year at a time.

If you’re claiming a refund you must file Form 1040 X within three years of the original tax return or within two years of the time you paid the taxes (whichever is later). For more detailed instructions on how to complete Form 1040 X visit the IRS website and download the 12 page instruction document.


Amending your federal returns may have an affect on your state returns, so make sure to review your state returns.

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Category: Form 1040X, Tax Forms, Taxes

About the Author ()

Felicia A. Williams is a wife, mother, freelance writer and owner of Tidbits About Money.

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