After four quarterly updates, the Final Declaration is where you sign off the year. It is the MTD-era replacement for the annual Self Assessment return.
Four quarterly updates do not, on their own, calculate your tax. They are running totals of income and expenses, nothing more. The figure that actually determines what you owe HMRC is produced at the Final Declaration, the moment you confirm the year is complete, fold in everything the quarters left out, and accept the calculation. Get the quarters right but skip the Final Declaration and you have not filed at all.
Making Tax Digital for Income Tax splits the year into two kinds of submission. The first is the quarterly update: four cumulative snapshots of your business income and expenses, sent through compatible software. These give HMRC a near-real-time view but deliberately ignore a lot, dividends, savings interest, employment income, Gift Aid, pension contributions and most reliefs.
The Final Declaration is where all of that comes together. It is a single submission, made after the tax year ends, that finalises your business figures and brings in every other source of income and every relief you are entitled to. Only then is your full Income Tax and National Insurance bill calculated.
It also took over the job of the End of Period Statement, the per-business confirmation step HMRC scrapped in 2024. There is now just one year-end action, not several.
The Final Declaration deadline mirrors the familiar Self Assessment date: 31 January following the end of the tax year. For the 2026/27 tax year, the first year MTD is mandatory for many sole traders, the timeline looks like this:
| Submission | Period covered | Deadline |
|---|---|---|
| Quarter 1 update | 6 April to 5 July 2026 | 7 August 2026 |
| Quarter 2 update | to 5 October 2026 | 7 November 2026 |
| Quarter 3 update | to 5 January 2027 | 7 February 2027 |
| Quarter 4 update | to 5 April 2027 | 7 May 2027 |
| Final Declaration | full 2026/27 year | 31 January 2028 |
Any tax owed is also payable by 31 January 2028, and payments on account for the following year may fall due on the same date and the following 31 July. See how the MTD for ITSA framework sequences these stages.
Take Daniel, a self-employed plumber. His quarterly updates report £62,000 of income and £14,500 of expenses across 2025/26, a net profit of £47,500. But the quarters miss several things, which is exactly what the Final Declaration captures.
| Item | Amount | Where it is added |
|---|---|---|
| Net trading profit (from quarters) | £47,500 | Quarterly updates |
| Capital allowances on a new van | -£9,000 | Final Declaration adjustment |
| Pension contribution relief | claimed | Final Declaration |
| Dividend income from ISA-external shares | £1,200 | Final Declaration |
| Personal Allowance (2025/26) | £12,570 | Final Declaration calculation |
After the van's capital allowances reduce his profit to £38,500 and the Personal Allowance is applied, the bulk of his income is taxed at the 20% basic rate, with Class 4 National Insurance at 6% on profits above £12,570. None of those reliefs or the dividend appeared in the quarterly totals; they only land at the Final Declaration. To estimate your own year-end position before you reach it, the quarterly planner is a good starting point, and our blog covers each MTD change in detail.
A common misunderstanding is that filing four quarters means you are done. You are not. The quarterly updates are intentionally incomplete; they exclude reliefs and non-business income so that they stay quick and frequent. The Final Declaration is the only point at which your actual liability is settled and legally confirmed. Skipping it leaves your return open and your tax unpaid, with the same late-filing consequences that applied under Self Assessment.
The quarters keep HMRC informed; the Final Declaration is what actually closes the year and fixes your tax bill.
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