MTD ITSA final declaration deadline (31 January)

For taxpayers within Making Tax Digital for Income Tax, the final declaration replaces the SA100 self-assessment return. It is due to HMRC by 31 January following the end of the tax year.

What is this filing?

The final declaration consolidates the four quarterly updates and any end-of-period statements (one per income source) into a single annual figure, applies reliefs and allowances, and triggers the balancing tax calculation.

When is it due?

31 January following the tax year end. For the first tranche of MTD ITSA (taxpayers with income above £50,000 from April 2026), the first final declaration is due 31 January 2028.

What's the penalty for missing it?

Same penalty regime as the SA100: £100 immediate, £10/day after 3 months, 5% of tax due (or £300) after 6 and 12 months. Late payment surcharges as for Self Assessment.

How PenaltyProof helps

PenaltyProof's MTD ITSA monitoring (paid plans) covers both the four quarterly updates and the 31 January final declaration.

Frequently asked questions

When is the first MTD ITSA final declaration due?

For taxpayers mandated from April 2026 (qualifying income above £50,000), the first final declaration covers the 2026–27 tax year and is due 31 January 2028.

Does the final declaration replace the SA100 completely?

Yes, for taxpayers within MTD ITSA. They do not file an SA100; the final declaration submitted through MTD-compatible software serves the same purpose.

What is the difference between the final declaration and the end-of-period statement?

An end-of-period statement (EOPS) is filed per income source (e.g. one for self-employment, one for rental) after the tax year ends. The final declaration combines all EOPS figures, applies reliefs and allowances, and confirms the total liability.

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