How to fix a filed return with Form 1040-X

When do you need to amend?

Amend if something important was wrong.

• You left off income, such as a 1099 you found later
• You missed deductions or credits you were entitled to
• Your filing status or dependents were wrong
• You got a corrected form, like a K-1 or corrected 1099

You generally don't need to amend for math errors or a forgotten attachment. The IRS usually corrects math, and it'll write to you for missing forms.

How do you file Form 1040-X?

1. Pull the original return and any notices about it.
2. Complete Form 1040-X, showing the original figures, the change and the corrected figures.
3. Explain why, briefly, in Part II.
4. Attach any forms that changed.
5. E-file it, if your software supports that year, or mail it.

Allow up to 16 weeks or longer for processing. You can check Where's My Amended Return after about three weeks.

How long do you have?

To claim a refund, you generally have three years from the date you filed or two years from when you paid the tax, whichever is later. If you owe extra, there's no deadline that protects you, but file and pay soon to cut down on interest. If you got an extension, your window's measured from when you actually filed.

What about your state return?

If the change affects your state income, you'll usually need to amend there too, often within a set number of days. It's easy to forget.

What if the IRS already wrote to you?

If you've got a notice, read it first. A CP2000 has its own response process, and filing an amendment may just muddy it. Respond to the notice instead, unless it tells you otherwise.

What about business returns?

Partnerships and S-Corps use their own processes. An S-Corp amends with Form 1120-S and an amended K-1, while most partnerships follow the BBA rules with Form 1065-X. If your K-1 changed, your personal return usually needs a Form 1040-X as well. We can prepare the corrected return for you to sign through our personal return service.