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.
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If you have filed Self Assessment before, you already understand 90% of the Final Declaration. It declares all your income, lets you claim reliefs and allowances, and calculates your tax bill — exactly as before. The only difference is that your self-employment and property income figures arrive pre-populated from your four quarterly updates rather than being entered from scratch.
How the Final Declaration Fits With Quarterly Updates
Q1 Update — 7 August 2026 — Income/expenses, 6 April–5 July
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Q2 Update — 7 November 2026 — Income/expenses, 6 July–5 October
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Q3 Update — 7 February 2027 — Income/expenses, 6 October–5 January
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Q4 Update — 7 May 2027 — Income/expenses, 6 January–5 April
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Final Declaration — 31 January 2028 — Combines all 4 quarters + other income + reliefs → calculates total tax owed
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
✅ Already Covered (from quarterly updates)
Self-employment turnover totals
Self-employment expense totals
Property rental income totals
Property expense totals
➕ Added in Final Declaration Only
PAYE employment income
Pension income (state + private)
Dividend income
Savings and bank interest
Capital gains (where applicable)
Foreign / overseas income
Other taxable income (e.g. trusts)
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
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Why this matters during the year: Don't be alarmed if your quarterly updates show a higher "income" figure than you expect to actually pay tax on. Quarterly updates show gross totals before allowances are applied. Your actual tax liability — after the Trading Allowance, Personal Allowance, pension relief, and everything else — is only calculated at the Final Declaration stage.
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.
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Not covered by the soft landing. The 2026–27 soft landing protects you from penalty points for late quarterly updates. It does not protect the Final Declaration. Miss 31 January 2028 and you receive a penalty point immediately, plus the standard late filing and late payment penalties that have always applied to Self Assessment.
Note that HMRC has indicated the existing Self Assessment late filing and late payment penalty regime continues to apply to the Final Declaration in addition to the new MTD points system for quarterly updates — 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
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.
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.
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.
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.
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.
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.
Get Your Full MTD Calendar
Our free calculator generates an ICS file with all four quarterly deadlines plus your Final Declaration date — add it directly to your phone calendar.