Form 1040-X: amending an individual return

When should you amend?

• You left out income, such as a Form 1099-NEC or 1099-K.
• You missed a deduction or credit you qualified for.
• You used the wrong filing status or claimed the wrong dependents.
• You received a corrected Form W-2, 1099 or K-1 after filing.

Do not amend for arithmetic errors, which the IRS corrects itself, or to send a schedule the IRS has asked for in a letter; reply to the letter instead. If you received a CP2000 notice, respond to it rather than amending. See CP2000 notice.

How do you complete Form 1040-X?

1. Get the original return

   And the corrected documents.

2. Complete the three columns

   Original amounts, the net change, and corrected amounts.

3. Explain each change

   In Part II, briefly and specifically.

4. Attach changed schedules

   Only those that change, such as Schedule C or SE.

5. File it

   Electronically where your software allows, or by mail.

How long do you have?

A return filed early is treated as filed on its due date for the three-year rule.

What if the amendment shows tax due?

Pay with the amendment to stop interest growing. Interest runs from the original due date, and a late payment penalty may apply. See how to pay the IRS.

What does an example look like?

A sole proprietor filed a 2025 return showing $60,000 of Schedule C profit, then received a late Form 1099-NEC for $4,000 she had not recorded. Her 1040-X shows the original profit in column A, $4,000 in column B and $64,000 in column C, with the related increases in self-employment tax and the small increase in her QBI deduction. Part II explains: "Additional nonemployee compensation received after filing; Schedule C, Schedule SE and Form 8995 updated." She pays the extra tax with the amendment.

Do you also amend the state return?

Usually yes. Most states require an amended state return when a federal change affects state income, often within a set period after the federal amendment. Check your state's form and deadline.

What happens after you file?

Amended returns take longer than original returns, often several months. Track progress with the IRS's Where's My Amended Return tool, usually from about three weeks after filing. Amend your state return too if the change affects it.

How do business changes flow through?

A change to Schedule C changes more than income tax. It also changes Schedule SE, the deduction for half of self-employment tax, and the qualified business income deduction on Form 8995, and possibly credits and estimated tax penalties. Recalculate each one, attach every schedule that changes, and keep a worksheet showing how the new figures were reached. If a partnership or S corporation issues a corrected Schedule K-1, amend for the corrected amounts. See Schedule SE and Form 8995.

Does amending increase the chance of an audit?

Amending does not by itself cause an audit, and correcting an error yourself is far better than the IRS finding it. Amended returns are reviewed, so make sure each change is supported by documents you keep with your records for at least three years after filing the amendment.

How do non-residents amend?

A Form 1040-NR is amended by filing a new Form 1040-NR with the amended return box checked, not Form 1040-X. See Form 1040-NR. Business returns have their own processes: partnerships use Form 1065 with the amended box or an administrative adjustment request, and corporations use Form 1120-X.

For business entity returns, see how to amend a business tax return.

This guide is general information. It is not tax or legal advice for your situation.