If you discover an error after your return has been mailed, you may need to amend your return. The service center may correct errors in math on a return and may accept returns with certain forms or schedules left out. In these instances, do not amend your return!

However, do file an amended return if any of the following were reported incorrectly:

Use Form 1040X(PDF), Amended U.S. Individual Income Tax Return, to correct a previously filed Form 1040(PDF), Form 1040A(PDF), Form 1040EZ(PDF), or TeleFile return. [If you are filing to claim an additional refund, wait until you have received your original refund (you may cash that check)]. To avoid penalty and interest, if you owe additional tax for 2004, you should file Form 1040X and pay the tax by April 15, 2005.

Be sure to enter the year of the return you are amending at the top of Form 1040X. The form has three columns. Column A is used to show original or adjusted figures from the original return. Column C is used to show the corrected figures. The difference between the figures in Columns A and C is shown in Column B. There is an area on the back of the form where you explain the specific changes being made on the return and the reason for each change. If the changes involve another schedule or form, attach it to the 1040X. For example, if you are filing a 1040X because you have a qualifying child and now want to claim the Earned Income Credit, you must attach a Form 1040 Schedule EIC(PDF) to show the qualifying person's name, year of birth, and social security number.

Generally, to claim a refund, Form 1040X must be received within 3 years from the date you filed your original return or within 2 years from the date you paid the tax, whichever is later.

If you are filing more than one amended return, be sure to mail each in a separate envelope to the service center for the area in which you live. The Instructions for Form 1040X list the addresses for the service centers.

Please Note: Your state tax liability may be affected by a change made on your federal return. For information on how to correct your state tax return, contact your state tax agency.