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tax-deadlinesUpdated 2026-02-27

What is the MTD Final Declaration?

Quick Answer

The Final Declaration replaces the traditional annual Self Assessment tax return under MTD. It confirms your final income and expenses for the tax year and is due by 31 January after the end of each tax year.

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Detailed Explanation

The Final Declaration is the annual submission required under Making Tax Digital for Income Tax Self Assessment. It replaces the traditional Self Assessment tax return (SA100).

What it does: - Confirms your final income and expenses for the tax year - Allows you to make adjustments to the quarterly estimates you submitted throughout the year - Includes any additional income sources not covered by quarterly updates (e.g., bank interest, dividends) - Calculates your final tax liability for the year

When it is due: The Final Declaration is due by 31 January after the end of the tax year. For example: - 2026/27 tax year → Final Declaration due 31 January 2028 - 2027/28 tax year → Final Declaration due 31 January 2029

How it differs from quarterly updates: Quarterly updates are provisional estimates of your income and expenses submitted every three months. The Final Declaration is your definitive annual figure. You can adjust any estimates made in quarterly updates.

Penalties: The Final Declaration is subject to the penalty points system even during the soft landing year (2026/27). Missing the 31 January deadline earns a penalty point and may trigger a fine if you have already accumulated points from other late submissions.

Submission: Filed through your MTD-compatible software, not through the old HMRC Self Assessment portal.

Source: HMRC MTD ITSA — Final Declaration Guidance

Real-World Examples

Adjusting Quarterly Estimates

You submitted four quarterly updates estimating £52,000 total self-employment income. After reviewing your full-year records, the actual figure is £54,500. Your Final Declaration corrects this and HMRC recalculates your tax.

Including Additional Income

Your quarterly updates only covered self-employment income. In your Final Declaration, you also report £2,000 in bank interest and £8,000 in dividends, giving HMRC the complete picture of your annual income.

Soft Landing Year Penalty

It is the 2026/27 soft landing year. You submitted all quarterly updates late (no points issued due to soft landing). But you also miss the 31 January 2028 Final Declaration — this does earn a penalty point because the Final Declaration is not covered by the soft landing.

Common Mistakes to Avoid

  • Assuming the Final Declaration is the same as the old Self Assessment return — it is filed through MTD software, not the HMRC Self Assessment portal.
  • Thinking the soft landing year protects you from Final Declaration penalties — it does not.
  • Not including additional income (interest, dividends) in the Final Declaration — quarterly updates only cover trade and property income.
  • Treating quarterly updates as final and not reviewing them before the Final Declaration.

Do I still file a Self Assessment return under MTD?

No. The Final Declaration replaces the Self Assessment return for income covered by MTD ITSA. You submit it through your MTD-compatible software.

Can I change my quarterly figures in the Final Declaration?

Yes. Quarterly updates are provisional. The Final Declaration is where you confirm or adjust your figures for the full year.

What if I have income not covered by MTD?

The Final Declaration allows you to report all income sources for the year, including those not part of quarterly updates (bank interest, dividends, foreign income, etc.).

Is the Final Declaration deadline always 31 January?

Yes. The deadline is always 31 January following the end of the tax year, the same as the current Self Assessment deadline.

Practical Tips

  • Use the Final Declaration as your annual financial review — check all quarterly figures are accurate before confirming.
  • Gather information about bank interest, dividends, and other income before filing your Final Declaration.
  • Do not wait until 31 January — your MTD software can generate the Final Declaration as soon as the tax year ends on 5 April.
  • Set a reminder for December to start preparing your Final Declaration, giving you a full month before the deadline.

Related Questions

What is Making Tax Digital (MTD)?

Making Tax Digital is HMRC's initiative requiring businesses to keep digital records and submit returns using compatible software. VAT is already under MTD; Income Tax follows in April 2026.

What do I need to report in MTD quarterly updates?

You report category totals of income and expenses — not individual transactions. Self-employment categories include turnover, cost of goods, wages, travel, and professional fees. Property categories include rent received, repairs, insurance, and mortgage interest.

What happens if I miss a Making Tax Digital deadline?

MTD uses a points-based penalty system. You receive one point per late submission. At four points, you receive a £200 fine. Points reset after 24 months of full compliance.

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