Even if you have taken every precaution to file an error-free tax return, there may be details you overlook which can lead to future problems. The IRS corrects errors such as miscalculations and informs you of the changes. For example, if you made a mistake in taking the Earned Income Credit (EIC), then the IRS will correct the error and send you a notice to inform you if you owe any money. The IRS may also correct errors involving the Making Work Pay and Government Retiree Credit.

If the IRS corrects the error and you are not required to attach any forms or schedules, then you do not need to amend your return. However, if there is a required change in your filing status, income, deductions or credits, then you must file an amended return. For instance, if you claim a credit that you do not qualify for, then you will need to file an amended return to correct that error.

To amend your return, you may use Form 1040X, Amended U.S. Individual Income Tax Return. To file an amended return, you cannot do so electronically. You will need to paper file your amended return and mail it to the address included in the instructions on Form 1040X.

Form 1040X has three Columns: A, B and C. Column A shows the original figure before the amendments. Column C shows the corrected figure. Column B is reserved for an explanation of the changes that you are making. If you need to attach certain tax forms with your amended return, then you may do so.

If you owe taxes after the correction of any errors, you then need to pay the amount before the filing deadline. After the deadline, the IRS will treat the taxes owed as back taxes. The difference between owing taxes before the filing deadline and after is that the IRS will begin charging penalties and interest on any delinquent balance.