Fill Out a US 1040X Tax Return

In the event that there is an error on your 1040 tax return, don't panic, the 1040-X comes to the rescue. Following a few simple steps, you will be able to correct most mistakes. Depending on which amendments you are making, you may not have to fill out the entire form.


IRS Form 1040X

Doc:IRS Form 1040X

Getting Started

  1. Find your old tax form instructions. You'll need to use the instructions that were released the same year as the tax return you are amending. Search for old instructions on the irs website and view them online or print them to refer to while you work on your 1040X.
  2. Check the calendar year you are amending. Check one of the boxes at the top of the page, so the IRS knows which year you are amending. Choose the year for which you were reporting income, not the year you sent in the tax return.
  3. Fill out the basic information. No matter what your reason for amending the tax return is, enter your name, current address, and social security number. You only need to fill out your spouse's information if you checked "married" on the original tax return, or if you checked single but are now amending it to married status.
    • If you are amending it from a single to a "married, filing jointly" return and your spouse did not file a return for that year, make sure to enter your name first.
  4. Add an explanation. Part III of Form 1040X is a blank space where you should write the reason for amending your tax return. You can leave this until after you've filled out the rest of the form if you like, but don't forget to write an explanation before submitting.
  5. Check which section you need to fill out. Look at the list below to find out which sections of 1040X you need to complete, then refer to the sections below that give instructions for those lines. Any lines that are not included next to your reason for amendment, you can leave blank.
    • File status: To amend this, fill out Lines 1–23 of 1040X
    • Exemptions: Lines 1–30
    • Income or Adjustments to Income: Lines 1–23
    • Itemized or standard deductions: Lines 1–23
    • Tax before credits: Lines 5–23 (If this is the only change, just use original data for line 5, then start with the tax liability section below.)
    • Nonrefundable credits: Lines 6–23
    • Other taxes: Lines 6–23
    • Payments and refundable credits: Lines 10–23 (If this is the only change, just use original data for lines 10 and 11, then start with the payments section below.)
    • If you are not sure which information you are amending, look at the old tax return you are amending. The line with the mistake should be in a section with one of the titles above.
  6. Know how to use columns A, B, and C. Most of the lines on 1040X have three columns. Write the original (incorrect) value in column A, exactly as it appears on your original tax return. Write the amount of the correction in column B, with a + or - sign in front of it (or write 0 if there is no difference). Write the net result in column C (even if this is the same as column A).
    • For example, if you originally reported $40 of income, but discovered you earned $20 more, you would write "40" in column A, "+20" in column B, and "60" in column C.
    • If your original tax return has already been amended once, or if the IRS made corrections, use the amended or corrected values in column A.

Amending Income and Deductions (Lines 1–5)

  1. Enter your adjusted gross income. Fill out all three columns on line 1. For the value in column A, refer to one of the following lines, depending on which form you used for your original return:
    • Form 1040 line 37
    • Form 1040A line 21
    • Form 1040EZ line 4
  2. Calculate other changes. If your adjusted gross income changed, return to your original tax form instructions to recalculate anything that used the value you entered for adjusted gross income. This includes child credits, education credits, maximum itemized deductions, and other credits that are calculated based on your adjusted gross income.
    • If your itemized deductions changed, fill out and attach a Schedule A (Form 1040) with the new itemized list. Alternatively, switch to the standard deduction for that year.
  3. Enter your exemptions. If you are amending your exemptions, refer to the instructions below for lines 24–30 to find out what to put in line 4. If you are not making changes, enter the following from your original form:
    • Form 1040: the value on line 42
    • Form 1040A: the value on line 26
    • Form 1040EZ: see this chart.
  4. Calculate taxable income. Once you have exemptions calculated, subtract line 4 from line 3 and enter the result here. If you did not need to make any changes to line 1 through 4, enter the taxable income amount on your original tax form.
    • If your original reported taxable income was $0 and your actual taxable income has changed due to changes in lines 1–4, Column A should show the actual amount, not 0. Use Column B for additional amendments you are reporting, if necessary.
    • If the taxable income is negative, enclose it in parentheses.

Amending Tax Liability (Lines 6–11)

  1. Find the tax information you need. In most cases, you can write "Table" in the "methods used" line, and use the instructions that accompanied your old tax return, which you can search for here. You must use the form for the correct year, as the tax table changes each year. Alternatively, use the same website to find a tax computation worksheet, and enter "TCW" in methods used. If using a specialized form due to a less common income source, use the following forms as well, for the year of the original return:
    • Schedule D Tax Worksheet (write Sch D in addition to other methods used).
    • Schedule J (Form 1040) (Sch J)
    • Qualified Dividends and Capital Gain Tax Worksheet (QDCGTW)
    • Foreign Earned Income Tax Worksheet (FEITW)
    • Form 8615, Tax for Certain Children Who Have Unearned Income (F8615)
  2. Enter your nonrefundable credits. If you made any changes to lines 1–4, you'll need to refer to the original tax return instructions to recalculate the nonrefundable credits. In column A, write the recalculated credits, not the original amount reported. Use column B to report additional changes, if necessary. Find the original credits reported on your old form here:
    • Form 1040: 2014: lines 48–54 ; 2010–2013: lines 47–53
    • Form 1040A: 2014: lines 31–35 ; 2010–2013: lines 29–33
    • Form 1040EZ: 2014: lines 7–8b ; 2010–2013: n/a
  3. Complete this section. Lines 8 and 11 are simple math instructions, but you'll need a little more data for lines 9 and 10:
    • Health care: Leave blank if tax return was for 2013 or earlier. For 2014, see 1040 line 61 / 1040A line 38 / 1040EZ line 11.
    • Other taxes: Leave blank if you used 1040A or 1040EZ. For 1040 from 2014, see line 57-62. For 1040 from 2011–2013, see lines 56–60. Changes listed in Form1040X lines 1–6 can affect these taxes, so read the instructions for your old form to recalculate if necessary.

Amending Payments (Lines 12–17)

  1. Gather additional forms if necessary. This is not necessary in most cases, but you'll need to refer to and attach additional forms if they have changed:
    • If changing the amount of Social Security or RRTA tax withheld or given in excess, attach any additional or correct W-2 forms and/or 1099-R forms you received after filing your original return.
    • If claiming an Earned Income Credit (EIC) and have a qualifying child, attach Schedule EIC (1040) or Schedule EIC (1040A).
    • If you are adding a nontaxable combat pay to your EIC calculations, but already submitted the W-2 with that pay included, you do not need to attach anything. Just explain the situation in Part III of Form 1040X.
    • If the IRS disallowed (rejected) an EIC claim, read the explanation at the top of Form 8862 to determine whether filling out and attaching that form is required.
    • Attach any of the forms listed under line 15, if you are making an amendment to that form or an amendment that requires you to fill out one of those forms. If filling out a new one, find the form for the tax return's year here.
    • Refer to Form 4868 if you filed an automatic extension, or Form 2350 if you applied for an extension.
    • If you have a Form 8689 Allocation of Individual Income Tax to the U.S. Virgin Islands, add lines 40 and 45 together and write the result on the dashed line to the left of 1040X line 17, writing "USVI" next to it. Add this amount to lines 12–16 when calculating line 17.
  2. Recalculate your EIC if necessary. If you made changes to 1040X line 1 or line 5, then you may need to recalculate your EIC. See your original tax return instructions for the following lines:
    • Form 1040: line 64a (66a in 2014)
    • Form 1040A: line 38a (42a in 2014)
    • Form 1040EZ: line 8a
  3. Refer to your original tax return to complete the section. The remainder of this section should only require copying values from your original return into column A, and reporting amendments in column B if there are any. Use this chart to find the information on your old return:

Amending Refund or Amount You Owe (lines 18–23)

  1. Calculate line 18. This information is found on Form 1040 line 73 (or 75 in 2014); Form 1040A line 42 (or 47 in 2014); and Form 1040EZ line 11a (or line 13a in 2014). If the IRS corrected your original tax return, use the corrected amount instead.
  2. Calculate your new tax result. Follow the arithmetic instructions for lines 19, 20, 21, 22, and/or 23. Note that you will not need to fill out all of these, as the results will tell you that you either owe the IRS additional money, or the IRS owes you an additional refund.
    • If the result for line 19 is negative, write it as a negative number. When calculating line 20, keep in mind that you can [[Add-and-Subtract-Negatives|subtract a negative number] by ignoring the negative sign and treating it as an addition problem.

Amending Exemptions (Lines 24–30)

  1. Refer to your original instructions. You do not need to fill out this section unless you are amending the exemptions listed on your original tax form. Refer to the instructions for Form 1040 or 1040A, for the year you filed the tax return, and look up the Exemptions information that applies to you, in order to make alterations to lines 24–27. Add up these lines to complete line 28.
  2. Check whether you need the line 29 worksheet. Based on line 28, determine your next step. Whichever method you use, don't forget to put the final result on line 4 of 1040X as well as line 29:
    • If you are amending exemptions from 2012 or earlier, skip ahead to the simple exemption step below.
    • If you are amending exemptions from 2013, refer to the list of incomes below. If 1040X line 1 is less than the amount listed below for your filing status, skip ahead to the simple exemption step. If instead you made more money than listed below, you must use the "Deduction for Exemptions Worksheet" in the instructions for the form and year of your original tax return:
      • Married filing separately: $150,000
      • Married filing jointly or Qualifying widow(er): $300,000
      • Single: $250,000
      • Head of household: $275,000
    • If you are amending a return from 2014, the IRS has not yet determined this amount. Check this document to find out whether this has changed.
  3. Use the simple exemption calculation. If the step above referred you to this step, use the method below to calculate step 29, based on the year of your tax return:
    • 2013: Multiply line 28 by $3,900
    • 2012: Multiply line 28 by $3,800
    • 2011: Multiply line 27 by $3,700
  4. List your dependents. Include dependents claimed on your original tax return as well as newly claimed dependents. Do not include dependents that you originally claimed but are now amending to remove the claim.


  • If there are tax forms relevant to your amendments, attach them. For instance, attach a W-2 that you did not report on the original tax return, or fill out and attach a Schedule A (Form 1040) to list new itemized deductions.
  • Normally, although you can file an amended return for almost any year, you can only file the 1040-X for a refund when amending a tax return from the last three years. However, the IRS can require that you file an amended return to make corrections up to seven years past.
  • Part II is optional. Check the box if you changed your mind and want $3 of your tax to go to a special fund for low-funds presidential candidates instead of to other purposes.


  • If you are amending a tax return from 2010 or earlier, or from 2015 or later, some of the line numbers that refer to your original tax return may not correspond to your document. (The line numbers for 1040X should be unaffected.)

Things You'll Need

  • Pencils
  • Calculator
  • Original tax return you are amending (1040, 1040A, 1040EZ)
  • Supplemental forms if necessary (described throughout instructions when needed)

Related Articles

Sources and Citations