California Conformity to Federal Law

Overview

In general, California tax law conforms to the Internal Revenue Code (IRC) with modification. However, there are differences between California and federal tax law. Certain specific areas of conformity and nonconformity are discussed in the affected tax forms instructions and in our Supplemental Guidelines to California Adjustments (Publication 1001).

On October 1, 2025, Senate Bill 711, the Conformity Act of 2025 was enacted. The Act changed California’s specified date of conformity to the IRC from January 1, 2015, to January 1, 2025.

Summary of federal income tax changes

• 2020 – 2022, 2024 (no report for 2023)
• 2019 Report-Part I (PDF)
• 2019 Report-Part II (PDF)
• 2018 report (PDF)
• 2017 report (PDF)
• 2016 report (PDF)
• 2015 report (PDF)