Fixing a filed return: Form 1040-X, deadlines, and checking your refund

A corrected W-2 shows up in March. A 1099 turns up in a drawer in June. You realize you never claimed a credit you qualified for. The return is already filed, and the question is what to do now. The answer is usually Form 1040-X, the amended return, but not always, and the timing matters more than people expect. This page covers when to amend and when not to, the deadline for getting money back, how to file, and how to track both an amended return and an ordinary refund.

When to amend, and when not to

Amend when something that affects the tax changes: your filing status, income, deductions, credits, dependents or the tax itself. ¹

Don't amend in these situations:

• The IRS already fixed it. If the IRS corrected an arithmetic error while processing your return, there is nothing to amend. ¹
• A form was missing. If the IRS accepts your return without a schedule or form, it will ask you for it if it needs it. ¹
• You received a CP2000 and simply agree with it. If the IRS proposes a change for unreported income, you agree, and you have nothing else to report, you answer the notice and don't need to amend. If you do have other changes, the IRS asks for a Form 1040-X with "CP2000" written at the top, sent with your response. My page CP2000, decoded explains the rest. ⁶

One amended return covers one tax year. If a mistake carried into several years, you file a separate Form 1040-X for each. ¹

The deadline for a refund

If the amended return will get you money back, there is a clock. Generally, you must file it within 3 years of the date you filed the original return, or within 2 years of the date you paid the tax, whichever is later. ¹ A return filed early is treated as filed on the April due date, so the 3 years count from then. ¹

There is a second limit inside the first. Even if you're in time, the refund can't be more than the tax you paid within a lookback period before the claim, generally 3 years plus any extension if you filed within the 3-year window. ⁴ Extended deadlines can apply for federally declared disasters, combat zone service and some other situations. ¹

If the amendment means you owe more, there is no deadline to wait for. File and pay as soon as you can, because interest runs on tax not paid by the original due date, even if you had an extension to file. ⁵

How to file Form 1040-X

E-file it if you can. Most tax software can e-file Form 1040-X. ¹ You have to paper-file in two cases: you filed the original return on paper earlier this year for a prior tax year, or the return is for an older year the e-file system no longer takes. ¹ You can e-file up to three amended returns for the same year. ¹

Fill it in three columns. The form has a column for the original amounts, one for the net change and one for the corrected amounts, plus a section in Part II where you explain the change in plain words. ⁵ Attach any forms or schedules that changed.

Remember your state. A federal change often changes your state return too. The state has its own amended return; don't attach it to the federal one. ¹

Checking the status

An amended return: Where's My Amended Return?

Give it time before you look. The IRS says status appears about 3 weeks after you submit Form 1040-X, that processing generally takes 8 to 12 weeks, and that some returns take up to 16 weeks. ² Returns with errors, missing information or a missing signature, or that involve identity theft, can take longer. ²

The tool covers this tax year and 3 prior years, and asks for your Social Security number, date of birth and ZIP code. You can also see the status in your IRS Individual Online Account. ²

An ordinary refund: Where's My Refund?

For the original return, the tool is different. The IRS says you can check about 24 hours after e-filing a current-year return, 3 days after e-filing a prior-year return, and 4 weeks after mailing a paper return. ³ Most e-filed refunds arrive within 3 weeks; mailed returns take 6 weeks or more. ³ It asks for your Social Security number or ITIN, filing status and the exact refund amount. ³

What to gather

• A copy of the return as filed, including every schedule.
• The new or corrected forms (W-2c, a late 1099, a credit form).
• Your original refund amount, or the amount you paid.
• Any IRS notice you've received for that year.