Amended Returns & Form 1040X
Question: What should I do if I made a mistake on my federal return that I have already filed?
Answer: It depends on the type of mistake that you made:
Many mathematical errors are caught in the processing of the tax return itself.
If you did not attach a required schedule, the IRS will contact you and ask for the missing information.
If you did not report all your income or did not claim a credit, you should file an amended or corrected return using Form 1040X (PDF), Amended U.S. Individual Income Tax Return.
When filing an amended or corrected return:
Include copies of any schedules that have been changed or any Form W-2 (PDF) you did not include.
Generally, to claim a refund, the Form 1040X (PDF) must be received within three years after the date you filed your original return or within two years after the date you paid the tax, whichever is later.
Please allow the IRS 8-12 weeks to process an amended return.