How to amend a tax return

File an amended return when something that affects your tax was wrong on the return you filed. One current example: if you already filed your 2025 return and want to claim or change the new “no tax on tips” deduction, the IRS says you may amend it. The December 2025 revision of Form 1040-X has a line for the new Schedule 1-A deductions for tips, overtime, car loan interest and seniors.

One change you generally cannot make: once you have filed a joint return, you cannot switch to separate returns for that year after the due date.

Otherwise, these are the changes the IRS lists as reasons to amend:

Not every mistake needs a Form 1040-X. The IRS corrects certain errors itself, such as math mistakes, and lets you know. If you left out a form or schedule, it either accepts the return without it or writes to ask for it. In both cases there is nothing to amend.

Two other cases call for something else. A refund of only penalties and interest you already paid is claimed on Form 843, not Form 1040-X. And once the due date has passed, do not send a second original return for a year you already filed, even if you have not heard back: the IRS says a duplicate can delay your refund.

Form 1040-X works line by line in three columns. Column A is the amount on your return as filed, or as already adjusted by you or the IRS; column B is the increase or decrease; column C is the corrected amount. The tax is then refigured on the corrected numbers, which gives the refund or the balance due. You explain each change on the form and attach any form or schedule the change affects, such as the new Form W-2.

Use a separate Form 1040-X for each year you are correcting, and only once the original return for that year has been filed. You can amend the same year more than once, as long as each one is filed on time.

A federal change can affect your state tax as well, and the state return is corrected separately with your state tax agency, not attached to the 1040-X.

If the amendment means money back, you generally have to file it within three years after you filed the original return, including extensions, or within two years after you paid the tax, whichever is later. A return filed early counts as filed on the April due date, and tax withheld from your pay or paid as estimated tax counts as paid on that date too.

The amount is capped as well. A claim filed within the three years can recover tax paid in the three years before it, plus any extension; otherwise, only tax paid in the two years before it. Miss the deadline and, unless an exception applies, the refund is lost. Claim only what you can support: a refund claim for more than the correct amount can bring a penalty of 20% of the part that is disallowed, unless you had reasonable cause.

Some situations allow more time:

You can file Form 1040-X electronically, with tax software or through a preparer who e-files, for the current tax year and the two before it. Two cases still go on paper: any older year, and a prior-year return that you originally filed on paper during the current year.

An e-filed amendment is a full corrected return, with every form and schedule included, not just the ones that changed, plus the 1040-X. If a preparer files it, you sign a new Form 8879 for each one. You can e-file up to three amended returns for the same year, and an e-filed 1040-X can ask for the refund by direct deposit.

Do not expect e-filing to make it fast. The IRS says it may save a week or two of mailing time; processing an amended return is still a manual job.

File and pay as soon as you can. If the original due date for that year has not yet passed, filing the correction and paying by that date avoids penalties and interest; an extension of time to file does not move that date. After it, interest runs on the unpaid tax, even if you had an extension.

Do not work out interest or penalties yourself or put them on the 1040-X; the IRS figures them and adjusts your account. If you then do not pay within 21 calendar days of the IRS’s notice and demand for the extra tax, a late-payment penalty, usually 0.5% a month, applies. The IRS prefers electronic payment, and an e-filed 1040-X can authorize a direct debit for the balance.

If you cannot pay it all at once, you can ask to make monthly installment payments, as with any other balance due.

The IRS tracks amended returns in its own tool, Where’s My Amended Return, which is separate from Where’s My Refund. A 1040-X shows up in it about three weeks after you submit it, and the IRS says to allow 8 to 12 weeks for processing, in some cases up to 16. The tool covers the current year and up to three prior years and asks for your Social Security number, date of birth and ZIP code. The same status is available by phone at 866-464-2050.

Some returns never appear in it: business returns, carryback claims, injured spouse claims, a Form 1040 marked as amended instead of a 1040-X, amended returns with a foreign address, and returns handled by a special unit such as Examination or Bankruptcy. Returns that have errors, are incomplete or unsigned, include an injured spouse allocation, or are affected by identity theft can take longer than 12 weeks. Call the IRS about the status only if the tool tells you to.

When your return does show, its status is one of three: