MTD Final Declaration Explained —
The Replacement for Self Assessment
If quarterly updates are the new, unfamiliar part of Making Tax Digital, the Final Declaration is the reassuringly familiar part. It is, in essence, your old Self Assessment tax return — same deadline, same purpose, same legal weight. Just arriving at the end of a year that also included four quarterly updates.
How the Final Declaration Fits With Quarterly Updates
Your four quarterly updates provide the running totals for your self-employment and property income and expenses. The Final Declaration takes those totals, adds everything that quarterly updates don't cover, applies any reliefs and allowances, and produces your final tax calculation for the year.
What Goes Into the Final Declaration
Reliefs and Allowances — Claimed Here, Not Quarterly
A common question from people new to MTD is: "where do I claim my allowances?" The answer is: the Final Declaration, not the quarterly updates. Quarterly updates simply report income and expense totals — they do not apply personal reliefs or allowances. Those are all handled at the Final Declaration stage, exactly as on the old Self Assessment return:
- Trading Allowance. £1,000 tax-free allowance for small amounts of self-employment income
- Property Allowance. £1,000 tax-free allowance for small amounts of property income
- Personal Allowance — the standard tax-free amount of income everyone receives
- Marriage Allowance — transferring a portion of personal allowance between spouses
- Pension contribution relief — higher and additional rate relief on pension contributions
- Gift Aid — extending basic rate band for charitable donations
- Capital allowances — claims for plant, machinery, and equipment (Annual Investment Allowance, writing-down allowances)
- Loss relief — offsetting business losses against other income or carrying forward
The 2026–27 Final Declaration Deadline
| Tax Year | Final Declaration Due | Balancing Payment Due |
|---|---|---|
| 2026–27 | 31 January 2028 | 31 January 2028 |
| 2027–28 | 31 January 2029 | 31 January 2029 |
The deadline structure is unchanged from Self Assessment: 31 January following the end of the tax year, both for filing and for paying any balancing tax owed. If you make payments on account (advance payments towards next year's tax bill), the existing 31 January and 31 July payment-on-account structure also continues unchanged.
Final Declaration Late Penalties
| Situation | Penalty |
|---|---|
| Late filing (1 day late) | 1 penalty point (MTD points system) + £100 fixed penalty (legacy SA-style) |
| Late filing (3+ months) | Additional daily penalties of £10/day, up to £900 |
| Late payment (after 30 days) | 5% of unpaid tax, repeated at 6 and 12 months |
| Late payment interest | Daily interest from the payment due date |
Under HMRC's guidance, the new points-based penalties replace the existing Self Assessment late filing and late payment penalties for MTD taxpayers. Your 2025–26 Self Assessment return (due 31 January 2027) is still under the current rules — meaning the Final Declaration carries both the legacy SA-style penalties and a points-system penalty point if missed.
What Your Software Does at Final Declaration Time
Most MTD software providers build a Final Declaration tool directly into their platform. In practice, this means:
- Your quarterly update totals are automatically pulled through. No re-entry required
- You are prompted to add any income not covered by quarterly updates (PAYE, pension, dividends, etc.). often by entering figures from your P60, dividend vouchers, and pension statements
- The software calculates available allowances and prompts you to claim relevant reliefs
- A final tax calculation is shown before submission — similar to the "tax calculation" summary at the end of the old Self Assessment process
- You review, confirm, and submit — and the figure for tax owed (or refund due) is generated
Can You Amend a Final Declaration After Submitting?
Yes. As with the old Self Assessment return, you can amend a Final Declaration after submission, generally within 12 months of the original filing deadline. If you discover an error after submitting, for example, you forgot to include some dividend income, or claimed the wrong relief — you can submit an amendment through your MTD software in the same way you previously amended a Self Assessment return online.
Frequently Asked Questions
What is the MTD Final Declaration?
The Final Declaration is the annual submission that replaces the old Self Assessment tax return under Making Tax Digital. Due by 31 January following the end of the tax year, it finalises your tax position by combining your four quarterly update totals with any other income such as pension, PAYE, dividends, and savings interest, and calculates your overall tax liability.
Does MTD replace Self Assessment completely?
Yes, for taxpayers in MTD. The Final Declaration performs the same function as the old SA100 Self Assessment return — declaring all income, claiming reliefs and allowances, and calculating tax owed. The quarterly updates feed into this, but the Final Declaration is the legally binding annual submission.
When is the Final Declaration due for 2026-27?
The Final Declaration for the 2026–27 tax year is due by 31 January 2028 — the same deadline date as the old Self Assessment return, but covering a year that included MTD quarterly updates.
Is the Final Declaration covered by the MTD soft landing?
No. The 2026–27 soft landing covers late quarterly updates only. Missing the Final Declaration deadline of 31 January 2028 results in a penalty point regardless of the soft landing, and late payment penalties and interest apply to any unpaid tax from the payment deadline.
Can I claim allowances and reliefs in the Final Declaration?
Yes. The Final Declaration is where you claim the Trading Allowance, Property Allowance, Marriage Allowance, pension contribution reliefs, Gift Aid, capital allowances, and any other reliefs that were previously claimed on the Self Assessment return. These are not part of quarterly updates.
Do I still need an accountant for the Final Declaration?
This depends on the complexity of your tax affairs, just as it did under Self Assessment. Many sole traders with straightforward affairs complete the Final Declaration themselves through their MTD software. Those with complex situations, multiple income sources, capital gains, overseas income, or significant reliefs to claim — often continue to use an accountant, who can work within the same MTD software if given access.
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