What happens if I filed my return with missing or incorrect data?

"OH, NO! I forgot I worked that small side-job during the summer months and I just received my W-2 from that company reporting my earned income. Now what do I do?"

No sweat! There's an easy process for this very common circumstance.

The IRS has provided Form 1040X - Amended U.S. Individual Income Tax Return, to file what is referred to as an "amended" tax return. If you reported data incorrectly on your return or did not include a required piece of data, the 1040X allows for correcting your return. Once the 1040X is received it becomes your new return filed at the IRS for the current tax year.

Here's the process: (*Tip: stay-tuned below for how 1040.com makes this process smart and simple.)

1. Identify the mistake and/or missing data from your originally filed return.
2. Gather any additional documents you may need to re-file your corrected return. (*Tip: have your previously filed return in-hand)
3. Complete the top portion of the form with the required entries.
4. Complete Column A on the 1040X form with all applicable data (*Note: you may not need to complete  every line).
5. Complete Column B with the net change (increase or decrease) of income, deductions, credits, etc. for each line you are changing. 
   1. Example: if you forgot to include a W-2 as in the example above, Column B, line 1 would need to include that extra income.
6. Explain the changes made in Column B, in Part III on the second page of the 1040X. If you need more space, attach a schedule to the form.
7. Complete Column C -
   1. Add the increase in Column B to the amount in Column A, or
   2. Subtract the decrease in Column B from the amount in Column A
   3. For any amount you do not change, carry the amount from Column A, directly to Column C.

*NOTE: any negative amounts entered into Columns A, B or C should be in parentheses.

Example: Brian forgot to include a W-2 from a summer job. He originally filed his return, reporting $19,000 of adjusted gross income (AGI). Brian received an additional W-2 reporting the $1,000 he earned while on the job; he completes line 1 as follows:

*NOTE: If any additional federal withholding was reported on this W-2 in box 2, Brian would report this on line 11 in Column B.

You're almost done! Unfortunately, the 1040X must be mailed to the IRS - e-filing is not yet supported for this form:

1. Refer to the "Assembling Your Return" section of the 1040X instructions for directions on how to prepare your 1040X packet for mailing to the IRS. Pay specific attention to the "If you owe tax…" section for including a check for a balance due return.
2. Mail your 1040X and any supporting documents to the specific addresses outlined by the IRS in the section of the 1040X instructions labeled "Where to file" - page 4.

Related Links: How 1040.com Makes Filing an Amended Tax Return Smart and Simple

Referenced Documents: 1040X form (pdf),1040X filing instructions (pdf)