When filing your income tax return, it's important that you provide accurate information. An accurate tax return ensures that you pay all the taxes you owe or receive the full refund that you are due. It also protects you from prosecution in the event that your tax return is audited. If you originally filed California tax form 540A and made mistakes on it, then you will need to file California tax form 540X, the Amended Income Tax Return, and mail it to the California Franchise Tax Board.
Obtain a copy of California tax form 540X, the Amended Individual Income Tax Return. You can download the form from the California Franchise Tax Board website or you can call 800-338-0505 to request the form via mail.
Fill out your personal information at the top of the form. For item b, indicate if you are changing the filing status that you indicated on your original tax return.
Fill in information on income and deductions on lines 1 through 21 on Page 1 of Form 540X. For each line write the amount quoted in your original return in column A, the correct amount in column C and the net change in column B.
Complete the calculations required for lines 26a through 34 on Page 2 and enter the results in the boxes provided.
Skip "Part I" for Nonresidents on Page 2 of the form. This section is not applicable if you originally completed form 540A.
Complete "Part II" on Page 2 of the form. In the large blue box for item 5, you will need to explain each item on Page 1 that you amended, including the amounts changed and why the changes were necessary.
Sign the bottom of the form and fill in all personal information.
Attach your original California tax form 540A, your original federal tax return form, your amended federal tax return form (if applicable) and any supporting documents that explain the changes that you made. Write your Social Security number on all supporting documents.
Mail Form 540X and all additional documents to the California Franchise Tax Board. If you are due a refund or do not owe any additional tax, mail your return here:
Franchise Tax Board PO Box 942840 Sacramento, CA 94240-0002
If you owe money to the state, mail your return and a check or money order here:
Franchise Tax Board PO Box 942867 Sacramento, CA 94267-0001