What If I Just Realized I've Been Doing My Tax Returns Wrong?

If you filed a return but you need to make changes beyond correcting basic math errors or including missing W-2 forms, file Form 1040X, Amended U.S. Individual Income Tax Return, with the IRS, along with any additional paperwork you didn't include with your original return. You can download form 1040X and the instructions from the IRS website. However, you must print out the form and mail it in; you cannot file form 1040X electronically. You must file a separate Form 1040X for each tax year, and you must mail each form separately in its own envelope. Refunds from Form 1040X are issued by paper check, not by direct deposit; allow between eight and 12 weeks for receipt.

If you just need information from a tax return for a prior year to complete an amended return, the IRS provides free tax transcripts for the current tax year as well as for the past three years. You may request tax transcripts online at the IRS website, by phone or by mail. Tax return transcripts include most of the information entered on an original tax return, including supplemental forms and transcripts, but do not show any changes made after the return was filed. Tax account transcripts include basic data such as marital status and adjusted gross income, but also include adjustments you made or those made by the IRS after the filing of the original tax return.

Copies of actual tax forms filed in prior years are generally available for the current tax year and for the past six years. Download and complete "Form 4506, Request for Copy of Tax Return" from the IRS website. You must submit the form by mail and include payment of $57 for each tax return you request; allow up to 60 days to receive the requested copies.

If you mistakenly believed that you were not obligated to file a tax return for a previous year, don't file Form 1040X. Tax forms and instructions for many previous years are available from the IRS website. If you owe federal income tax, you should include payment along with your past year tax form. Although penalties for late payment will continue to accumulate, filing a return stops the clock on penalties for failure to file tax returns, which are often much stiffer. If the IRS filed a tax return for you under the Substitute for Return Program, file your own return anyway, especially if your return shows you owe less money or should receive a larger refund than the IRS calculated. The IRS usually makes adjustments based on the information you supply.

Time is of the essence when filing an amended or missing tax return to obtain a refund. To receive a refund on an amended tax return, you must file the return within three years of the date you filed your original return, including extensions, or within two years after you paid the tax on an original return, whichever is later. If you're filing a missing tax return, the IRS only generally allows you to claim refunds for the past three years.