On: August 10, 2018

3 years

If you have discovered a mistake in a tax returns that has already been filed, you can file an amended return, also known as Form 1040X. The Internal Revenue Service allows you to amend a return if your filing status is incorrect, your income is wrong, or you have incorrectly calculated deductions or tax credits. The IRS also sets a deadline on correcting an old return on a 1040X.

Deadlines

You indicate the year of the tax return you are amending at the top of the 1040X. For amended returns, the IRS sets up a deadline of three years from the date the original return was due. For example, if the due date of the return was April 15 2010, you have until April 15, 2013 to file a 1040X for the year 2009. If you paid the tax after you filed the return, then the deadline is 2 years from the date of your payment if that date would be later.

Refunds

The IRS will allow you to amend a return to increase the amount of your refund. However, the agency requires you wait until you receive the first refund before filing the amended return. When that refund arrives, you may deposit it and file the 1040X to claim the increase and an additional refund.

Additional Tax Due

Some taxpayers find they have made a mistake that means they owe additional tax. The IRS will correct your tax return if it has the information supporting a change in you outstanding tax liabilities. If it does not have that  information, you are well advised to file an amended return as soon as possible and pay the additional tax before the due date (usually April 15 following the tax year for individuals). If you do not get the additional tax payment in on time, the IRS may levy penalties and interest on the outstanding balance.

The IRS does not accept electronically filed amended tax returns.