You discover you made an error on your tax return, or maybe you've received a 1099 form that got lost in the mail (and that you'd forgotten to include when filing your taxes). If this occurs for a tax return filed within the past three years, refile your tax return using the IRS' 1040X form.
Step 1
Download and print, from the IRS website, a copy of Form 1040X. Print multiple copies if you will be amending multiple years. If you do not have a computer, contact the IRS to mail you the paperwork you need. Use Form 1040X to amend previously filed Forms 1040, 1040EZ or 1040Z.
Step 2
Mark the box for the tax year that is being amended. Enter the information originally filed in Column A. Use Column C for the new information. Calculate the difference and enter in Column B. Enter all information using a pen, because amended returns must be mailed to the IRS -- they cannot be e-filed.
Step 3
Complete the back of Form 1040X with the reason you are refiling your return. Complete additional forms or schedules if required because of the change. Make a copy of all paperwork for your records.
Step 4
Mail all paperwork, including documentation supporting the change, to the IRS at the address listed on the form. Use a separate envelope for each year if amending more than one year. Include payment if you owe money.
