Deadline for amendments to CA tax forms

California allows you to amend all prior year tax returns.

 

What it limits is how far back they will issue refunds:

Generally, you must file your claim for refund by the later of:

• 1 year from the date of overpayment
• 4 years after the original return due date.
  • If you filed before the due date, you have 4 years from the original return due date to file a claim.
  • If you filed after the extension, the return is late. You have 4 years from the original return due date to file a claim.
  • If you made payments and never filed a tax return, you have 4 years from the original return due date to file a claim.
• 4 years after the date of a timely filed return, if filed within the extension period.

 

This information and more is found here: California Amendments

How do I amend a California state return in TurboTax Online?

 

[Edited 2.20.24 | 5:09am]

Thanks for your input. The first link you sent is not the CA Franchise Tax Board - it's a site for vehicle registraton refunds, etc., it seems...? "The California Department of Tax and Fee Administration (CDTFA) administers California's sales and use, fuel, tobacco, alcohol, and cannabis taxes, as well as a variety of other taxes and fees that fund specific state programs."
I did find the info finally on the FTB site for income tax amendments and refunds, and it's 4 years after the original due date:
https://www.ftb.ca.gov/help/disagree-or-resolve-an-issue/claim-for-refund.html