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.

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