What is a final declaration?
Definition of final declaration
Final declaration is the term used by HMRC to describe the process a taxpayer goes through to finalise their end-of-year position for Income Tax. This process was formerly known as a ‘crystallisation’.
The final declaration process will be introduced in April 2026 as part of the Making Tax Digital for Income Tax initiative. This will replace the annual Self Assessment tax return for many taxpayers, and require those affected to keep their records digitally and file updates through accounting software.
Before starting the final declaration process, the taxpayer will need to ensure that their accounting software is up to date with their entire income for the year (including interest on savings and dividend payments) and any relevant additional information.
The final declaration process will then allow the taxpayer to finalise their tax position for the year and calculate their final Income Tax liability. The final declaration must be made by 31st January following the end of the relevant tax year.