Is there fee to e-file 1040X ?

You should be able to file an amended return for free if you filed with a paid version of TurboTax.

If you want to make changes or add a document to a tax return that has already been filed and accepted by the taxing agency, you should follow these guidelines. 

• You must first wait until the initial return is completely processed.
• You will have to use the same TurboTax account that you used for the original tax return.
• Once you begin your amendment, you'll see your original return.
• The refund calculator will start new at $0 and only reflect the changes in the refund or tax due
• Only make changes to the areas of your return that need to be corrected.
• You have three years from the date you filed your return or two years after you paid the tax due (whichever is later) to file an amendment

Select your product below and follow the instructions. 

Amend TurboTax Online 

Amend TurboTax CD/Download 

Thanks CatinaT.

I filed my original return via TT 2024 Premier Desktop version several weeks ago . Both IRS and CA have processed my original return successfully.  So you meant I can now e-file both Federal and CA amended return via my TT 2024 Premier Desktop version for free, right? Thanks again.

Correct.  You should be able to e-file your amended returns for free.  There are some people, due to the changes that end up needing to print and mail their returns, but in general you should be able to e-file. 

Thanks for the quick answer. Your answer convince me I should do the  amended return this weekend. Lastly, just curious, what kind of changes can potentially end up needing to print and mail their returns ?

Anything that would require you to attach a form.  If your changes require a separate form submission ar statement TurboTax will let you know that they need to be mailed.

@popomama1 

Thanks. In my case, I missed 1099-INT.  Do you mean I need to mail in the amended return in this case? I would assume IRS already have the 1099s.

No, you should be able to add the details of the 1099-INT and then e-file the amended returns.   A missing 1099 is one of the most common reasons taxpayers have to file amended returns.   As long as you file the amended returns by 10/15/25, you should have no issues filing them electronically.  @popomama1 

Thanks for the confirmation.