If you are familiar with Self Assessment, you know the annual ritual of completing your tax return and submitting it by 31 January. Under Making Tax Digital, the annual tax return is replaced by something called the Final Declaration. This guide explains what the Final Declaration is, what it contains, when you submit it, and what happens once it is submitted.
The Final Declaration is an end-of-year submission that replaces the Self Assessment tax return for income covered by Making Tax Digital. It is the point at which you confirm your total income and expenses for the year, include any adjustments, claim additional tax reliefs, and finalise your tax position with HMRC.
Throughout the year you submit four quarterly updates containing summary totals of your income and expenses. Those quarterly updates give HMRC a picture of your income as the year progresses. The Final Declaration is where you confirm and finalise everything, correcting any estimates, adding income from other sources, and claiming any reliefs you are entitled to.
The Final Declaration must be submitted by 31 January following the end of the tax year. This is the same deadline as the current Self Assessment tax return. Any tax owed is also due on 31 January.
For the tax year ending 5 April 2027, the Final Declaration deadline would be 31 January 2028.
The Final Declaration brings together everything relevant to your tax position for the year:
Once you submit the Final Declaration, HMRC calculates your total tax liability based on everything you have reported. This includes Income Tax on your total income, National Insurance if applicable, and any other amounts due.
HMRC sends you a calculation through your MTD software or directly. This tells you exactly how much tax is due and by when it must be paid. Payment is due by 31 January.
Payments on account, advance payments toward the following year's tax bill, work the same way as under the current Self Assessment system. If your tax bill is above a certain threshold, HMRC will require payments on account in July and January.
In practical terms, the Final Declaration covers much of the same ground as the current Self Assessment tax return. The key differences are:
The underlying tax rules, what income is taxable, what expenses are allowable, which reliefs you can claim, remain unchanged. Only the reporting method changes.
If you have income that is not covered by MTD, such as employment income, bank interest, dividends, or capital gains, you still need to report it. This is done through the Final Declaration process, which combines your MTD income with any non-MTD income sources to produce a complete picture of your tax position.
HMRC intends to pre-populate some of this information, for example employment income reported through PAYE and bank interest reported by financial institutions. Landlords will need to review and confirm this information before submitting the Final Declaration.
As with the current Self Assessment system, you can amend a Final Declaration after submission if you discover an error. HMRC will then recalculate your tax liability based on the corrected information. Interest may apply on any underpayment.
SimplifyMTD guides landlords through the Final Declaration step by step. Your quarterly submissions are already recorded in the system, so the figures carry forward automatically. You confirm your totals, add any adjustments, and submit through the same secure HMRC connection used for quarterly updates.
The guided process ensures you do not miss any required steps, from confirming income and expense totals to claiming the finance cost restriction and completing the declaration itself.