How to Amend a Tax Return: IRS Form 1040X

Manny Ramirez
Sep 14, 2025
2 min read

Updated: Jan 9

Amending Your Tax Return 1040X: Image of Man Filling Out Tax Form — Image of Man Filling Out Tax Form

If you’ve already filed your taxes and realized something is missing or incorrect, don’t panic—IRS Form 1040X, Amended U.S. Individual Income Tax Return, lets you fix it. At PennySmart Group in North Port, Florida, we help individuals and families understand how to amend a tax return for the most recent year and prior years.

How to Amend a Tax Return Using IRS Form 1040X

IRS Form 1040X is used to correct or update a previously filed federal tax return. Knowing how to amend a tax return properly can help you avoid penalties and recover refunds you may be owed.

Common reasons to amend a tax return include:

Adding forgotten income, such as a missing 1099
Claiming overlooked deductions or credits
Correcting your filing status (single, married, or head of household)
Fixing dependent information

Important note: Simple math errors do not require an amendment—the IRS automatically corrects those.

How to Amend a Tax Return: Filing Options

When learning how to amend a tax return, it’s important to understand your filing options. The IRS allows two methods:

E-Filing an Amended Tax Return

E-filing is available for amended returns for the most recent four tax years and is usually the fastest option.

Mailing an Amended Tax Return

Mailing is required for older tax years or when e-filing is unavailable. Always use the correct IRS mailing address listed in the Form 1040X instructions.

Refund Deadlines When You Amend a Tax Return

If you are owed a refund, timing matters. In most cases, you must amend a tax return within three years from the date you filed the original return or two years from the date you paid the tax, whichever is later. Missing this deadline could mean losing your refund.

How Long Does It Take After You Amend a Tax Return?

Amended returns take time to process. The IRS estimates up to 20 weeks, or about five months. Filing electronically and choosing direct deposit can help reduce delays.