If you make a mistake on a tax return you’ve already filed, the IRS allows you to correct those mistakes by filing an amended tax return. If the correction results in an increase in the amount of tax you owe, it’s to your advantage to file the amendment to avoid potential interest and penalties on the underpayment.
When to amend a tax return
The IRS allows you to file an amended tax return only to correct your filing status, the number of dependents you claim, your gross income and to increase or decrease the number of deductions and credits you report on your original tax return. If your original return reports the correct information but includes math errors, there is no need to file an amendment. The IRS regularly checks returns to ensure mathematical accuracy. In the event it finds a math error, your return is automatically recalculated. The IRS will notify you in writing of any recalculation and its effect on your tax bill or refund. When you file with TurboTax, our calculations are guaranteed to be 100% accurate.
Time limitations to amend
You have a limited amount of time to file an amended tax return; otherwise, the IRS will not accept it. This must be done by the later of three years from the original due date of the return, three years from the date you actually file if after the deadline or within two years of paying tax for that year. For example, if you file your 2010 tax return on March 15, 2010, then you have until April 15, 2014 to get your amended tax return to the IRS.
As a result, you have no obligation to file an amended tax return after the relevant limitation period even if the correction would increase the amount of tax you owe. However, the IRS will not issue a refund check for an amended return you file after the limitation period.
Preparing your amended tax return
The only way to amend a personal tax return is by filing Form 1040X. If the correction relates to items you report on a schedule, you must prepare a new schedule and submit it with the Form 1040X. For example, if you file an amended tax return because you omitted charitable deductions on your Schedule A, you must recalculate your itemized deductions and file it with your Form 1040X. Form 1040X does not require you to recalculate the entire tax return; rather, you only include line items that are affected by the change. The form also provides you with space to explain your reasons for filing the amendment.
State income taxes
When you amend your federal tax return, you may need to amend your state income tax return too. Most states calculate taxable income based on information you provide on your federal return. Therefore, any change you make to your federal return is likely to affect your state return. For example, if you file the amended tax return to increase your refund by adding the charitable contribution deduction you omitted, it may also reduce your state tax if it also allows for charitable deductions.