Ask Kim
How to Fix Past Tax Mistakes
By Kimberly Lankford, Contributing Editor, Kiplinger's Personal Finance
March 8, 2002
While I was preparing my 2001 taxes, I found some receipts for business equipment I bought in 2000. Can I change my old tax return?
Yes. You have up to three years after the original due date to file an amended return if you've made a mistake or left something out (seven years for changes regarding bad debt or worthless stock).
Download Form 1040x (PDF, 26.6 KB), print it out and copy the basic numbers from your original return -- adjusted gross income, deductions, exemptions, credits and taxes paid.
Specify the changes you're making. Since your change will affect your business income, you'll need to attach a new Schedule C. If you're changing other deductions, you'd need to attach a new Schedule A. For more information about the rules, see Instructions for 1040x (PDF 42.8 KB).
If you contribute to an SEP or Keogh plan, consider the domino effect your changes could cause. See IRS Publication 560, Retirement Plans for Small Business (PDF, 214 KB), for more information about contribution limits and rules.
You'll need to amend your state return, too. Contact your state's tax agency for forms and instructions.