December 2, 2016 1:40 pm

5 Things to Know About Amended Returns

Your 2015 and 2016 income tax returns have been filed, but you now discover an error. You forgot to take a write-off you were entitled to, made a math mistake, omitted an item of income, or failed to file a required form. What do you do? Decide whether to file an amended return.

1. Determine whether to amend

It was reported in the Wall Street Journal that about 3.7 million amended returns were filed in the government’s fiscal year ending September 30, 2015, so amending a return is not a rare event. It’s up to you to decide whether to file an amended return.

When it comes to math errors, if you filed electronically, it’s highly unlikely that there are any because your computer is designed to do calculations properly. But if you filed a paper return, math errors are possible. If you made a calculation error that resulted in a tax that is lower than what you really owed, you don’t have to file an amended return. In processing your return, the IRS will find the mistake and send you a bill.

If the error resulted in your having paid too much in taxes, then decide whether to file an amended return. A small overpayment on your part may not be worth the bother of filing an amended return. However, if the sum is substantial, the only way to recoup the overpayment is to file an amended return.

Watch for deadlines. If you’re owed money, you must file no later than 3 years after the date you filed your original return or within 2 years after the date you paid the tax, whichever is later.

2. There’s no electronic filing

An amended return is submitted on Form 1040X. You cannot file this form electronically; you must file a paper form. This is so whether your original return was filed on paper or electronically.

3. Use separate forms for different years

Regardless of which type of income tax return—Form 1040, Form 1040A, or Form 1040EZ—you used, there’s only one form for an amended return: Form 1040X. If you are making corrections to a return for more than one year, you must file Form 1040X for each such year.

4. Provide all required documentation

You must explain the substance of your amendment. This may require you to attach documentation to show what you mean. For example, if you received a Schedule K-1 from an investment after you filed your return and you owe tax on the income from the investment, attach a copy of the Schedule K-1 and your explanation of the late receipt of it to Form 1040X.

5. Understand audit risk

Most tax professionals agree that filing an amended return increases the chances that your return will be audited. While the overall risk is low, the added scrutiny for an amended return should be factored into a decision about whether to file. This is especially so where you’re seeking only a modest refund.

Still, a report from earlier this year from the Treasury Inspector General for Tax Administration admonished the IRS to improve its processing of amended returns to prevent inappropriate refunds. Thus, there’s reason for skepticism about how great the audit risk for an amended return really is.


Amending your federal income tax return may also necessitate your filing an amended state income tax return. If you are unsure about whether to file any amended return, or how to do it, consult with a tax professional.

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