What should you do when you discover an error on an already-filed tax return? In most cases, the answer is: prepare and file a correction or an amended return. Here’s a refresher on the rules.

  • What to amend. You don’t have to correct math errors on your already-filed original personal federal income tax return. Also, you don’t have to file an amended return if you forgot to attach your W-2 or a supporting schedule. The IRS will send notices for those mistakes.

    Situations that indicate an amended return is necessary include inadvertently not reporting income or deductions on the original return, incorrectly claiming too few or too many dependents, and changing your filing status.

  • What forms to use. Forms for amending already-filed returns typically have an “X” in the title. For example, you’d use Form 1040X to correct your individual federal income tax return, even if you originally filed Form 1040A or 1040EZ.

    Most payroll returns also have an “X” in the title to differentiate forms used for amendments (Form 941-X, for example), as do C corporations (Form 1120X). S corporation returns and information reports such as Form 1099 generally have a checkbox on the regular form to indicate you’re filing a corrected return.

  • When to amend. Normally you need to file an amended return within three years of the filing date of the original return.

    Amended returns tend to have a “ripple” effect, meaning you may also have to amend state filings, as well as prior-year federal returns affected by carryforward or carryback items.

If you discover an error on your tax return, please call our office for assistance.