With the tax-filing deadline far behind us, many Americans are focusing more on summertime plans than on IRS matters. But while you might think you're done with taxes for the year, you may have some additional legwork to contend with if you discover after the fact that the return you submitted contained an error.

Do you need to amend your tax return?

The IRS will generally spot and correct math errors in the course of processing returns, so if you happen to dig up your taxes and spot an addition- or subtraction-related mishap, there's a good chance you won't have to do anything but wait for the IRS to make its adjustments and tell you the results. On the other hand, there are some scenarios where you'll need to go through the process of amending your tax return.

Pencil resting on tax forms atop a pile of $100 bills

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For example, if you used the wrong filing status on your return, you'll need to file an amendment to get that point right. Similarly, if you claimed credits or deductions you shouldn't have taken, or if you failed to claim credits and deductions you were actually entitled to, then you'll need to file an amended return to set that straight.

Furthermore, if you realize after filing your return that you failed to report income, you'll need to not only amend your original tax forms, but pay the IRS the difference immediately. Otherwise, you'll risk racking up penalties and interest on the tax debt you neglect to pay. And if the opposite is true -- you overreported income -- you'll need to file an amendment to snag your refund.

How to file an amended tax return

Amending a tax return is pretty easy. Just download Form 1040X -- Amended U.S. Individual Income Tax Return -- and follow its instructions. You may need to include supporting documentation in conjunction with that form.

Keep in mind that changes to your federal tax return might also trickle down to your state tax return. For example, if you neglected to report income, that's something that could impact your state taxes, so be prepared to amend those as well.

Will amending a tax return open you up to an audit?

Regular tax returns are processed automatically by the IRS -- meaning they're run through software designed to spot red flags. Amended tax returns, however, are reviewed by actual people, and as such, the chances of an audit may be slightly higher.

That said, if you filed an amended tax return in the name of accuracy, then you really shouldn't have anything to worry about. For example, if you forgot to report investment income on your original return, and filed an amended return to correct for that fact, then the person who reviews your new tax forms will see that. Therefore, don't let your fear of an audit stop you from amending a return that's erroneous. If you don't make the necessary corrections, and your original return gets flagged, you could easily land on that dreaded audit list anyway.