Instructions to Fill Out Form 1040X

Please Remember
Form 1040X cannot be filed online; you have to file it only by paper. The returns must be filed as well as mailed separately for each year.

IRS tax Form 1040X is filled when you have made some errors in some previously filed income tax returns and need to amend them. You will have to be very careful regarding whatever new information you will be filling, as this changed data is recorded with the IRS. Also, remember that when you file an amended tax return, it is dealt with much more care and precision than your previous tax forms. Therefore, be extra vigilant and try not to make an error again in entering the important values. In case an error is still unearthed, the IRS will contact you accordingly. And, make sure you provide a lucid, logical explanation as to why you are filling this form (in part III). In the paragraphs below, you will understand how to fill out a 1040X tax amendment form.

The Purpose
  • The purpose of this form, as mentioned earlier, is to initiate corrections on other tax forms.
  • These forms may be any of the following – 1040, 1040EZ, 1040A, 1040NR, or 1040NR-EZ.
  • You can also fill this form if you have a carryback on unused credit or if you need to change the previously adjusted IRS amounts.
  • Apart from these, file the return if you have entered an incorrect filing status, tax credits, tax deductions, or income.
  • Another point is that this form must be filled only after the original return has been filed. And, in case of a credit (if you expect a credit, that is), submit this form within 3 years of filing the original one, not later.
  • If there is any tax refund, it will be sent to you in the mail.
  • After completing the form, you are supposed to send/mail it directly to the IRS, where it takes 2-3 months to be processed.
Instructions to Fill the Form


Step I


  • Go through the form carefully, to begin with.
  • You will find that it consists of 2 pages to be filled, while the other pages consist of the instructions.
  • Collect the prerequisites – a copy of the income tax return that you want to amend, Form 1040X, and IRS notices for adjustment.
  • On the first page of the form, you will find a check option line – the different check boxes mention the different years.
  • Remember, at one given time, you can fill the form only for one year. Fill another form if you need to make corrections for that year too.
  • Keep the other forms with you (the ones submitted previously); some of the data from those forms needs to be entered accurately on this form as well.
  • In the section to follow, fill out your personal details – name, address, social security number, spouse name, etc.
  • In the next part, you have to change the filing status. You have to fill this part any way, irrespective of whether you need to change the status or not.


Step II


  • The next section is titled, ‘Income and Deductions’.
  • On line 1, enter the adjusted gross income. This is your total income minus any adjustments.
  • On line 2, you have to mention the standard deductions.
  • Subtract this value from the adjusted gross income and enter the result on line 3.
  • Lines 4 and 5 will need to be filled only after completing part I on the next page.
  • The next section is titled, ‘Tax Liability’.
  • On line 6, enter the tax value and also the method, which you used to find out the tax. Refer to the tax table for the same.
  • If, however, you have changed certain income values, you may need to change the tax method adopted.
  • On line 7, enter the credits or carryback (if any).
  • Subtract this value from the value on line 6 and enter the result on line 8. Enter zero if the answer is negative.
  • Include other taxes on line 9. Refer to the values on Form 1040 for the same.
  • Add the values on lines 8 and 9, and enter the final value, i.e., total tax on line 10.


Step III


  • The next section is the ‘Payments’ section.
  • Line 11 contains the withheld federal income tax and the withheld tier 1 RRTA tax.
  • If you need to amend the values, refer to the corresponding values from the other tax forms or look up the tax chart.
  • Enter the approximate tax payments on line 12 (including the previous year’s amount.
  • If you wish to claim for EIC (Earned Income Credit), calculate the return and enter the value on line 13. Also, attach Schedule EIC (Form 1040A or 1040) to the form.
  • If you wish to amend any refundables from the other tax forms, check the corresponding box and enter the value on line 14.
  • Line 15 contains the entire amount paid, with taxes, before and after filing the form. You also need to add any amount you have paid in order to extend your filing time.
  • Add the values on lines 11 to 15, and enter the result on line 16. This is the total payment.


Step IV


  • The next section is the ‘Refund’ section.
  • If you have any overpayment from the previous years, enter it on line 17.
  • Subtract this value from the value on line 16 and enter the result on line 18.
  • On line 19, enter the amount you owe. If the total tax value (line 10) is more than the amount on line 18, you have to enter the difference on this line.
  • If the total tax is lesser than the amount on line 18, enter the overpaid amount on line 20.
  • Enter whatever amount you want to be refunded with (from the previous line) on line 21.
  • Enter the amount you want to be applied for as tax on line 22.


Step V


  • Now, you will find yourself on part I, page 2 of the form, which is titled ‘Exemptions’.
  • You will need to fill information in this part only if you change the number of exemptions.
  • On line 23, fill the number of exemptions for yourself and your spouse. And, if you are claimed to be someone’s dependent, you cannot file for a personal exemption.
  • On line 24, fill in the exemptions for your children (if any).
  • Line 25 contains the number of exemptions for your children again, i.e., those children who are not residing with you (due to a separation/divorce).
  • If you have any other dependents, fill in the number of exemptions for them on line 26.
  • Add all the exemptions and write the final value on line 27.
  • Now, multiply this number by the exemption amount. This amount is for the year for which you have claimed amendments. Enter the value on line 28.
  • This value should also be entered on line 4 of the previous page.
  • Subtract this value from the value listed on line 3. Enter the result on line 5.
  • Now, count all the dependents and enter the value on line 29. You are done with part I


Step VI


  • If you have not given USD 3 to the Presidential Election Campaign Fund on your previous return, you can do so in part II of this form.
  • On part III, you have to write an explanation regarding why you are filling Form 1040X, what changes you have made, etc.
  • Also, attach all the necessary new forms and documents.
  • Sign wherever necessary, and mail the form.

Do not take the trouble of filling this form if you have made small errors in the math calculations. These errors are automatically verified and corrected by the necessary software. File this only if important data has been incorrectly entered.