The Internal Revenue Service is all about documents. Virtually everything you send the IRS must have a paper trail or explanation, and the 1040X form is no exception. However, the IRS only requires certain enclosures with your 1040X, and in most cases, you won’t have to enclose as many forms as you did with the original 1040. Use 1040X to report changes in your income, dependents, deductions, credits or filing status.
TL;DR (Too Long; Didn't Read)
The forms you are required to enclose with your 1040X depend on the the specific changes you are making to your tax return.
Forms and Schedules
The changes you make on Form 1040X may affect schedules and forms you used or omitted from your original return. For example, if you add or remove itemized deductions from Schedule A, you’ll need to include a new Schedule A with the form 1040X. It's only necessary to include forms changed by your amendment. You don’t have to include a new 1040 Form because it's replaced by the 1040X. It also isn’t necessary to enclose forms omitted from your original return due to the amendment. For example, if you originally claimed a dependent child and the Earned Income Credit, and file Form 1040X to remove both, you don't need to include a new credit work sheet.
Taxpayers often receive a stray W-2 or 1099 after they file an original return. If this happens, don’t worry -- just report the extra income on Form 1040X and enclose the new income documents. In some cases, you may not get any documents for income you need to claim. If you were supposed to receive a W-2 or 1099, rest assured the IRS has its own copy from the employer. Make a note of that with the Form 1040X.
If you're reporting income that won't be documented by another party, leave a note describing the nature of the income in the "explanation of changes" box on Page 2 of Form 1040X. You don't have to send additional paperwork to explain undocumented earnings unless it's requested by the IRS.
Always use your current address on Form 1040X. If you’ve moved since you filed the original return, note your new address even if your original return shows your old address. The IRS uses the address on the 1040X to keep you updated on the amendment process. You’ll receive written correspondence if the IRS has any questions about your 1040X, and a letter when the amended return is finished.
Processing and Refunds
The IRS typically takes about eight-to-12 weeks to process 1040X forms. During the peak filing times of January through April, and again in October, expect processing to be closer to 12 weeks. The IRS only accepts 1040X forms by mail, which means you won’t be able to e-file the amendment. If your changes show an additional refund, you’ll receive your check by mail, but you must send the 1040X within three years of the original return's due date. If you're due a refund and miss this deadline, you forfeit your refund unless you meet IRS exceptions.
With a background in taxation and financial consulting, Alia Nikolakopulos has over a decade of experience resolving tax and finance issues. She is an IRS Enrolled Agent and has been a writer for these topics since 2010. Nikolakopulos is pursuing Bachelor of Science in accounting at the Metropolitan State University of Denver.