How to File an Amended Tax Return (Form 1040X)

An amended tax return (Form 1040X) is how you fix mistakes on your original tax return. You generally have three years from your original due date to amend, and IRS refunds usually take 8–12 weeks.

What Is Form 1040X (Amended Tax Return)?

An amended tax return (Form 1040X) lets you correct mistakes on your original tax filing. You typically have three years from the original due date to amend, and refunds usually take 8–12 weeks to process.

Form 1040X is not just another piece of tax paperwork. It’s specifically designed to show three things side by side:

• Column A: What you originally reported.
• Column B: The changes you’re making.
• Column C: The corrected numbers.

At the bottom, you’ll also explain why you’re amending. Think of it as telling the IRS: “Here’s what I said before, here’s the correction, and here’s why it matters.”

Filing an amended return keeps your IRS account current and helps avoid future complications like underpayment notices, penalties, or delayed refunds.

If you’re new to taxes, check out our First-Time Filer Guide before diving into amendments.

When Should You File an Amended Tax Return?

You don’t need to amend for every tiny mistake—sometimes the IRS has your back. For example, math errors are usually caught and fixed automatically. But you must file an amended return if the error affects your tax bill.

Common reasons to amend include:

• Forgetting to report additional income (like a late 1099).
• Missing out on eligible deductions or tax credits. Students should also check our Refunds Guide for Students for commonly missed credits.
• Using the wrong filing status (for example, Single when you qualified for Head of Household).
• Getting a corrected W-2 form after filing.

You usually don’t need to amend if:

• The IRS corrects simple math mistakes.
• The mistake doesn’t change your refund or tax owed.

Rule of thumb: if the error could change your refund, balance due, or taxable income, it’s worth amending.

How to Prepare Before You Amend

Before you dive into filing an amended return, you’ll need some prep work. Here’s your quick checklist:

1. Pull up your original tax return. You’ll need it for reference.
2. Gather corrected forms like W-2s, 1099s, or 1098s if they’ve been reissued.
3. Collect receipts or documents that support new deductions or credits you’re claiming.
4. Download Form 1040X (and its instructions) from the IRS website.
5. Decide whether you’ll e-file or paper file (more on that below).

Pro tip: You can order a transcript of your prior return directly from the IRS if you can’t find your copy.

Step-by-Step: How to File Form 1040X

Form 1040X may look intimidating, but it’s easier once you understand the process. Here’s the step-by-step guide:

1. Fill out personal info at the top (name, SSN, address, filing status).
2. Use the three columns:
3. • Column A = numbers from your original return.
   • Column B = the net change (increase or decrease).
   • Column C = your corrected totals.
4. Adjust income, deductions, and credits as needed.
5. Explain your reason in Part III. Keep it simple but clear (e.g., “Received corrected W-2” or “Claiming American Opportunity Credit missed on original return”).
6. Attach supporting schedules or forms that have changed.
7. Sign and date the return.
8. Submit either electronically (if eligible) or by mail. When you electronically file Form 1040X, you also need to submit a new Form 8879, IRS e-File Signature Authorization Form.

Remember: The IRS processes each amended return separately, so if you need to fix multiple years, you must file one Form 1040X per tax year.

Should You E-File or Paper File Form 1040X?

Taxpayers can file electronically for the current or two prior tax periods. For years before that, the amended return needs to be mailed.

E-filing perks:

• Faster than mailing.
• Immediate IRS confirmation that it was received.
• Reduced risk of errors.

Paper filing downsides:

• Longer processing time (up to 16+ weeks).
• No tracking until about three weeks after mailing.

However, paper filing is still the only option if you’re amending a prior year return before 2019 or dealing with unusual forms that aren’t yet supported electronically.

Always double-check that you’re on the official IRS website (look for the locked padlock icon) before downloading forms or filing online.

How Long Does an Amended Tax Return Take?

Here’s the answer to the most common question. On average, the IRS takes 8–12 weeks to process an amended return. It can sometimes stretch closer to 20 weeks, especially during peak filing seasons or if you filed on paper.

Refunds can be issued via:

• Direct deposit (fastest).
• Paper check (slower).

If you owe additional tax, don’t wait—make your additional tax payment as soon as possible to reduce interest and penalties.

How to Check the Status of Your Amended Return

The IRS offers a handy online tracker called “Where’s My Amended Return?”. You can use it to check the status of your amended return starting about three weeks after submission.

What you’ll need:

• Your Social Security Number.
• Date of birth.
• ZIP code.

The tool updates daily and shows progress for the current year and the prior three tax years.

If your return seems stuck in processing beyond 20 weeks, consider contacting the IRS directly.

State Tax Implications

Amending your federal return may create a ripple effect for your state tax return.

• If your federal numbers change, you may need to file an amended state return.
• Every state has its own forms and deadlines.
• Don’t attach your state form to your federal Form 1040X—the IRS won’t forward it.

Check your state’s Department of Revenue website for details.

Common Problems and Rejections

Most amended returns go through smoothly, but sometimes the IRS may reject or deny your changes.

Reasons for rejection include:

• Forgetting to sign the return.
• Missing supporting documentation.
• Using the wrong form for the wrong tax year.
• Filing after the IRS limits deadline.
• Return is incomplete or has significant errors.

Some rejections are more serious—especially if the IRS suspects fraud. The consequences can be costly. See our guide on False Returns & Penalties for details.

Deadlines and IRS Limits

The IRS has strict timelines for amendments.

• Three years from the original due date of your return (including extensions).
• Or two years from the date you paid the tax owed, whichever is later.

For example:

• If you filed your 2021 tax return on April 15, 2022, you have until April 15, 2025, to file an amendment.
• If you paid a tax bill later than that date, the two-year rule may apply instead.

Miss the deadline? You can still amend to correct your record, but you won’t get a refund.

How Much Does It Cost to File an Amended Return?

Good news: Filing an amended tax return with the IRS is free.

But depending on how you file, there may be costs:

• DIY via IRS forms: $0.
• Tax software: May charge a fee (often $25–$100 per amended return).
• Tax professionals: Fees vary widely but often range from $150 to $500+, depending on complexity.

If your amendment involves complicated deductions, multiple states, or business income, professional help may be worth the price.

See our Services Page for details on our fees.

Getting Help With Amended Returns

Need backup? You have options:

• IRS website: Official forms, FAQs, and instructions.
• Tax software: Guided support for amending returns.
• Tax professionals: Great for complex situations, audits, or large refunds.

If your amendment could save you hundreds or thousands of dollars, professional help often pays for itself.

Final Thoughts

Filing an amended tax return doesn’t have to be stressful. Whether you accidentally left out income, claimed the wrong status, or realized you missed a valuable credit, Form 1040X is your path to making things right.

Keep these three tips in mind:

1. Act within the IRS deadlines.
2. Gather documentation to support your claim.
3. Track your amended return so you know where it stands.

Consult with a tax expert if you need help with your amended return.