If, after filing your return, you find a mistake, you might need to revise it. The IRS may accept returns without specific forms or schedules and may rectify math problems on a return. There is no need to revise your return in these circumstances! If your filing status, income, deductions, or credits change, you must file an updated return.

In general, you must file Form 1040X within 3 years of the initial return filing date or within 2 years of the tax payment date, whichever is later, in order to request a refund. Extensions aside, returns submitted earlier than the deadline are regarded as being submitted on that day.

For each tax year that you are modifying, submit a separate Form 1040X. Send every form in its own envelope. Make sure to fill out the top of Form 1040X with the year of the return you are updating. Three columns make up the form.