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.

Disclaimer: The content included in this glossary is based on our understanding of tax law at the time of publication. It may be subject to change and may not be applicable to your circumstances, so should not be relied upon. You are responsible for complying with tax law and should seek independent advice if you require further information about the content included in this glossary. If you don't have an accountant, take a look at our directory to find a FreeAgent Practice Partner based in your local area.

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