How Long Do I Have to File an Addendum to My Taxes?

If you goof on your tax return, you can fix it within a limited time.
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It’s no fun to have to go back and fix mistakes after you’ve filed your tax return. The good news is that the Internal Revenue Service lets you file an addendum called an amended return. You don’t have to file an addendum for every little mistake, but if you do, the amount of time you have depends on whether or not you have to hand over more money to the IRS.

When Not to Amend

You might not need to file an addendum at all. The IRS says not to go to the trouble of sending in an amended return if you just left off some form or document. The IRS might take the return anyway. They will send you a notice if they want more info. The IRS checks your math, too. If you made a mistake with the numbers, their computers will correct it for you.

Getting Money Back

If you’re lucky enough to be owed a refund because of a mistake on your tax return, you have three years from the date you filed your original return to claim it by filing an amended return. That applies if you got a refund or paid everything you owed when you sent in that original return. If you had to take some extra time to pay money you owed based on the original return, you have the three years, or two years after you finished paying off the IRS, whichever is later.

When You Owe

The IRS doesn’t set a time limit for filing an amended return if a mess-up means you owe them more money. You want to file that addendum as soon as you can, though. You will be charged a late penalty and interest on what you owe starting the April due date of the original return. These extra charges just keep adding up until you pay what you owe. The sooner you file an amended return and pay your tab, the better.

The Amended Return

Don’t send in another 1040, 1040A or 1040EZ form if you mess up and have to file an addendum. Instead, the IRS says to use Form 1040X, “Amended U.S. Individual Tax Return.” You have to file the 1040X as a paper form because there isn’t any electronic version. You can download the form from the IRS website. Follow the instructions to complete the 1040X and attach any corrected schedules or forms. Mail everything to the address on the form. If you have to give the IRS more money, include a check or money order for the amount due.

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