MTD Final Declaration Explained: What to Send and When

The MTD final declaration is the year end submission that replaces your Self Assessment tax return once you are within Making Tax Digital for Income Tax. You send it through compatible software by 31 January after the tax year ends, and it is where you confirm your full income for the year and settle your tax bill. This guide explains what goes into it, how it differs from the quarterly updates, and how to get it right first time.

Key takeaways

• Quarterly updates are running summaries. The final declaration is the point where your tax for the year is actually worked out and confirmed.
• It is due by 31 January after the tax year, so 31 January 2028 for the 2026/27 tax year.
• It covers all your taxable income, not just self-employment and property, plus adjustments, allowances and reliefs.
• It must be sent through MTD-compatible software, not the old HMRC online return.
• Your 2025/26 return, due online by 31 January 2027, is still a normal Self Assessment return.

What is the final declaration?

Under Making Tax Digital for Income Tax, you keep digital records of your self-employment and property income and send HMRC a short update every quarter. Those updates do not finalise anything. After the tax year ends you complete one more step: you bring in everything else that affects your tax, make any accounting and tax adjustments, and declare that the information is complete and correct. That step is the final declaration.

You may see HMRC guidance describe this simply as submitting your tax return through your software. The label matters less than the job it does: it takes the place of the SA100 return you would otherwise file through your HMRC online account. An earlier version of the design also included a separate End of Period Statement for each business, but HMRC removed that requirement, so there is now one year end submission rather than several.

Who has to send one, and from when?

Anyone who is required to use MTD for Income Tax, or who has signed up voluntarily, sends a final declaration for each tax year they are in the system. The phasing is:

• Qualifying income over £50,000 in the 2024/25 tax year: MTD applies from 6 April 2026.
• Qualifying income over £30,000 in 2025/26: from 6 April 2027.
• Qualifying income over £20,000 in 2026/27: from 6 April 2028.

Qualifying income means gross self-employment and property income before expenses. Our guide to MTD qualifying income explains how it is measured, and you can check whether you need to use it on GOV.UK.

For the first group, the first MTD tax year is 2026/27. It ends on 5 April 2027 and the final declaration for it is due by 31 January 2028. That feels a long way off, but the records that feed it are being built right now, quarter by quarter.

Quarterly updates vs the final declaration

The quarterly dates are covered in detail in our guide to MTD quarterly update deadlines.

What goes into the final declaration

Think of it as everything a Self Assessment return would have asked for, assembled in software rather than typed into the HMRC website.

• Finalised business and property figures. The totals from your digital records for the full year, after you have corrected anything that was missed or miscategorised in the quarterly updates.
• Accounting and tax adjustments. For example capital allowances, private use adjustments, disallowable expenses, and any losses brought forward or carried back.
• Other income. Employment income and benefits, pensions, savings interest, dividends, and anything else taxable that is not already in your quarterly updates.
• Reliefs and allowances. Pension contributions, Gift Aid donations, Marriage Allowance transfers and similar claims.
• Other charges. Items such as student loan repayments or the High Income Child Benefit Charge, where they apply to you.

Some of this information may already be held by HMRC and pulled into your software, such as employment income reported through PAYE. You still need to check it. You are the one declaring that it is right.

Step by step: completing your final declaration

1. Close off the fourth quarter. Make sure the update for the period to 5 April (or 31 March if you use calendar quarters) has been sent.
2. Reconcile your records. Match your digital records to bank statements for the whole year so that nothing is missing or counted twice.
3. Correct earlier quarters. Fix the underlying records for any errors you find. See our guide to MTD digital records.
4. Enter year end adjustments. Capital allowances, private use, accruals if you use them, and losses.
5. Add your other income and reliefs. Gather P60s, interest statements, dividend vouchers and pension contribution records.
6. Review the tax calculation. Your software requests a calculation from HMRC. Read it. Compare it with last year and with the estimates you saw during the year.
7. Submit the declaration. Confirm the figures are complete and correct and send it.
8. Pay by 31 January. The balance for the year and any first payment on account are due on the same day.

Worked example (illustrative)

"Amara", an illustrative example, is a self-employed physiotherapist who also has a part-time employed role. Her self-employment turnover was above £50,000 in 2024/25, so she is in MTD for Income Tax from 6 April 2026.

During 2026/27 she sends four quarterly updates from her software. In February 2027 she notices that a batch of card payments was recorded twice in the second quarter. She corrects the records, and the corrected totals flow into her later submissions. After 5 April 2027 her accountant adds capital allowances on a treatment couch and a laptop, removes the private proportion of her phone bill, and brings in her employment income, a small amount of savings interest and her pension contributions. Amara reviews the calculation in September 2027, submits the final declaration that month, and knows exactly what she must pay by 31 January 2028, four months before it is due.

Nothing in this example is a real client. It simply shows the order of events and why finishing early leaves time to plan the payment.

Deadlines and penalties

The final declaration is due by 31 January after the tax year, the same date listed for online returns on the GOV.UK Self Assessment deadlines page. Tax for the year is due on that date too, with payments on account working in the usual way. Our guide to payments on account explains how those are calculated.

People within MTD for Income Tax fall under HMRC's points-based late submission regime and a separate set of late payment penalties. The rules, including any easements for the first year, have been adjusted more than once, so check the current position on GOV.UK rather than relying on an older article. Our overview of MTD penalty points explains the principle.

Common mistakes

• Assuming four quarterly updates mean you are finished. They do not. Without the final declaration your tax return for the year has not been filed.
• Forgetting non-business income. Bank interest, dividends and employment income all still need to be included.
• Trying to use the old HMRC online return. For an MTD year the submission is made through compatible software. See HMRC's list of compatible software and check your product supports the year end step, not only quarterly updates.
• Leaving adjustments until January. Capital allowances and private use calculations take thought. Doing them in the summer avoids a rushed job.
• Confusing the years. If you joined MTD on 6 April 2026, your 2025/26 return is still an ordinary Self Assessment return due by 31 January 2027.

How we can help

We look after the whole MTD cycle for sole traders and landlords: digital records, the four quarterly updates, year end adjustments and the final declaration. MTD compliance starts from £49 per month on a fixed fee. See our MTD Compliance service, check our pricing, or contact us to talk it through.