11 Tips on How and When to File an Amended Tax Return

What to do if you discover a mistake on a previously filed tax return (and other reasons for filing an amended tax return).

picture of a Form 1040x with a pen and calculator
(Image credit: Getty Images)

It's often said that everyone makes mistakes. And sometimes, when taxes are involved, some of those mistakes turn up on annual tax returns. Maybe you discover an error right after you filed your tax return, or perhaps months (or even years) pass before you realize that a new development changed the amount of tax that you should have paid on a prior return. Thankfully, whether the mistake is in your favor or, on the not-as-bright side, in the government's favor, filing an amended tax return can be the next best step.

Filing an amended return isn't particularly difficult, but there are a few things you should know about the process before getting started. It also helps to be familiar with some common occurrences that can trigger the need for an amended return. So, here are 11 tips on how and when to file an amended tax return.

Rocky Mengle
Senior Tax Editor, Kiplinger.com

Rocky is a Senior Tax Editor for Kiplinger with more than 20 years of experience covering federal and state tax developments. Before coming to Kiplinger, he worked for Wolters Kluwer Tax & Accounting and Kleinrock Publishing, where he provided breaking news and guidance for CPAs, tax attorneys, and other tax professionals. He has also been quoted as an expert by USA Today, Forbes, U.S. News & World Report, Reuters, Accounting Today, and other media outlets. Rocky has a law degree from the University of Connecticut and a B.A. in History from Salisbury University.