What is the final declaration?
The final declaration is the Self Assessment tax return for the tax year. It is submitted after the tax year has ended and covers the full 12 months.
While quarterly updates provide HMRC with a running summary of your income and expenses, the final declaration is the formal submission that calculates your final tax liability.
You must still submit the Self Assessment tax return for the tax year before you start using Making Tax Digital for Income Tax if you are newly signing up.
How it differs from quarterly updates
Quarterly updates are summaries of your income and expenses, built from digital records. They are cumulative from 6 April and are not tax returns.
The final declaration is a complete return that includes all income sources, including those not covered by quarterly updates such as employment income or dividends.
Quarterly updates are sent four times a year. The final declaration is sent once a year after the tax year ends.
| Feature | Quarterly updates | Final declaration |
|---|---|---|
| Frequency | Four times a year | Once a year |
| Content | Income and expense totals | Full tax return |
| Timing | During the tax year | After the tax year ends |
| Deadline | 7 August, 7 November, 7 February, 7 May | 31 January |
The 31 January deadline
The final declaration must be submitted by 31 January following the end of the tax year.
Tax is paid by 31 January. Late payment penalties apply if you miss this date, though payments on account are treated differently.
For the 2026-27 tax year, missing the tax return deadline will result in penalty points. Four points trigger a 200 pound penalty, with further penalties for subsequent missed deadlines.
Adjustments after the fourth update
The fourth quarterly update may need to be resent if you claim Rent-a-Room relief or have joint property expenses that are only known after the tax year ends.
These adjustments are made before the final declaration is submitted to ensure your tax calculation is accurate.
You can see an estimate of your tax bill in your software or in HMRC online services after each update.
Software and the final declaration
To submit the final declaration, you need compatible software that can create digital records and send quarterly updates.
An all-in-one product also submits the tax return. You can use more than one product, but records must be digitally linked between them.
TradeKit is MTD ready - recognised by HMRC (reference D4K6ZS).