If you made a mistake or missed a deduction, file an amended return on Form 1040-X. You do not need to amend for a simple math error, because the IRS corrects those itself.
When to file an amended return
- Wrong filing status, income, deductions or credits.
- You received a corrected tax form after filing.
- You forgot to include income.
Deadline
To claim a refund, file within three years of the date you filed the original return, or within two years of the date you paid the tax, whichever is later.
Steps
- Wait until your original return is processed.
- Complete Form 1040-X showing the original, changed and corrected amounts.
- Attach changed forms and schedules.
- File electronically if the IRS allows it for that year, or mail it.
- Track progress with the IRS “Where’s My Amended Return” tool.
Amended returns are processed manually and can take up to 16 weeks, sometimes longer.