After Your Quarterly Updates: The Final Declaration Deadline Explained

Your Quarterly Updates Are Done. But Your Filing Isn't.

There is a common assumption among people who are new to Making Tax Digital: once you have filed your fourth quarterly update, you are finished for the year. You have sent your income and expenses to HMRC, four times over, and surely that is the job done. It is not. The quarterly updates are just one part of the process. There is a separate, final step that sits at the end of every tax year - and missing it carries real consequences. This guide explains what the MTD final declaration deadline actually is, what you need to do before you reach it, and why the next eight months after your last quarterly update are more useful than most people realise.

What Is the Final Declaration?

Under Making Tax Digital for Income Tax (MTD ITSA), the tax year runs from 6 April to 5 April. During that year, you file four quarterly updates - each one reporting your income and expenses for that three-month period. Think of those updates as rough totals sent in stages. They give HMRC a running picture of your business income. But they are not a complete tax return.

The final declaration is the step where you complete the picture. It is where you:

• Confirm or adjust the figures you sent during the year
• Add income that does not go into quarterly updates - such as employment income, dividends, savings interest, or pension income
• Claim allowances and reliefs that cannot be claimed in quarterly updates - such as the personal allowance, the trading allowance, or pension contributions
• Report any losses and decide how to use them
• Make adjustments for things like private use of business assets

In short, the final declaration is your complete, whole-picture tax filing for the year. It is the equivalent of what the old Self Assessment tax return did. Until you submit it, your tax for the year is not settled.

The Deadline: 31 January 2028

For the 2026-27 tax year - the first year most sole traders and landlords will be in MTD - the final declaration deadline is 31 January 2028. That is the same date that Self Assessment tax returns have always been due for online filing. The deadline has not changed; what has changed is that there is now more to do before you reach it.

Missing the 31 January deadline means late filing penalties. HMRC's penalty system for MTD is points-based. You collect a point for each missed deadline, and once you reach a threshold, a financial penalty is charged. The final declaration deadline is no different. You can read more about how penalties work in our guide to MTD penalties explained.

The Timeline After Q4

Let us put the dates in order so you can see where the final declaration sits in the process.

If you are on Quarter Type A (the most common type, which starts 6 April), your quarterly deadlines for 2026-27 look like this:

• Q1 (6 April to 5 July 2026) - deadline 7 August 2026
• Q2 (6 July to 5 October 2026) - deadline 7 November 2026
• Q3 (6 October 2026 to 5 January 2027) - deadline 7 February 2027
• Q4 (6 January to 5 April 2027) - deadline 7 May 2027

Once you have filed Q4 by 7 May 2027, you have roughly eight months before the final declaration is due on 31 January 2028. That might sound like a long time. But those eight months are also when you need to gather the information that quarterly updates never asked for.

Not sure which quarter type applies to you? Read our guide to which MTD deadline applies to you.

What Your Quarterly Updates Do Not Cover

This is the part that catches many DIY filers out. Quarterly updates only cover certain types of income - mainly income from self-employment and property rental. They do not cover everything that might affect your tax bill for the year.

The final declaration is where you report:

Employment income

If you are a sole trader who also works as an employee - even part-time - your employment income does not go into your quarterly updates. It gets reported in the final declaration using your P60 (the document your employer gives you after the tax year ends, showing what you earned and what tax was deducted). We have a full explanation of this in our post on employment income and MTD quarterly updates.

Dividends

If you own shares and receive dividends, those are not part of your quarterly updates. They go into the final declaration. You will need your dividend vouchers or statements from your investment platform.

Savings interest

Banks now report interest directly to HMRC in many cases, but you still need to declare it correctly in your final declaration if it affects your tax position.

Pension income

If you receive income from a pension, this is reported in the final declaration, not in quarterly updates.

Capital gains

If you sold a property or other asset during the tax year and made a gain, that is reported separately. Capital gains are not part of quarterly updates or the final declaration in the standard sense - they go through the Capital Gains Tax pages. But you will need to have dealt with them before your overall tax position is settled.

If you have any of these income types alongside your self-employment or property income, the quarterly updates you filed during the year were always only a partial picture. The final declaration is where everything comes together.

Our post on MTD quarterly updates vs Self Assessment goes into more detail on what each step covers.

Allowances and Adjustments You Can Only Claim in the Final Declaration

Quarterly updates collect your raw income and expenses. They do not apply the allowances that reduce your tax bill. Those are all handled in the final declaration.

The personal allowance

Most people in the UK can earn up to £12,570 per year before paying income tax. This is called the personal allowance. It is applied automatically in the final declaration - you do not need to calculate it yourself - but it is part of why the final declaration is what actually determines what you owe.

The trading allowance

If your gross self-employment income is £1,000 or less, you may be able to claim the trading allowance instead of deducting actual expenses. This is a choice you make in the final declaration. Our post on the trading allowance for sole traders explains how it works.

The property allowance

Landlords with gross rental income of £1,000 or less can claim the property allowance instead of actual expenses. Again, this is a final declaration choice.

Pension contributions

If you pay into a personal pension (not through an employer), you can claim tax relief on those contributions. This is done in the final declaration, not in quarterly updates.

Losses

If your self-employment or property business made a loss during the year, you can choose how to use it - offsetting it against other income, carrying it forward to future years, or carrying it back to a previous year. These decisions are all made in the final declaration.

Adjustments for private use

If you claimed expenses during the year that were partly personal - for example, a phone you use for both work and personal calls - you should adjust the figure in the final declaration to reflect only the business portion. Our guide to mixed-use expenses and MTD explains how to work out the split.

Why Confusion Peaks After Q2

Most of the questions we hear about the final declaration do not come at the start of the tax year. They come in November and December - after Q2 is filed, when people start to wonder what happens next and whether they have already done enough.

The answer is that quarterly updates are necessary but not sufficient. You are doing the right thing by filing them on time. But they are the foundation, not the roof. The final declaration is the step that closes the year, confirms your tax position, and triggers any tax payment or refund.

You can read more about what happens after you file a quarterly update in our post after your first MTD quarterly update: what happens next.

A Practical Checklist: What to Gather Now

You do not need to wait until January 2028 to start preparing. In fact, the worst thing you can do is leave everything until the last few weeks. Here is what to collect as the year progresses.

Income records outside your quarterly updates

• P60 from any employer (issued after 5 April each year)
• P11D if your employer provided benefits in kind (such as a company car)
• Dividend statements or vouchers from shares you hold
• Savings interest statements from banks or building societies
• Pension payment summaries

Allowances and adjustments

• Records of personal pension contributions made during the year
• Any Gift Aid donations (which can extend your basic rate tax band)
• Notes on mixed-use expenses you claimed during quarterly updates that need adjustment
• Records of any business assets sold during the year

Loss records

• If you made a loss in a previous year and chose to carry it forward, keep a note of the amount - you may be able to use it against this year's profit
• If you made a loss this year, decide before the final declaration whether you want to offset it or carry it forward

Your quarterly update figures

• Keep copies of what you submitted for each quarter - income, expenses, and totals
• If you need to correct anything before the final declaration, our guide to amending a quarterly update after filing explains when it is worth doing

For a more detailed breakdown of what records to gather specifically for the final declaration, read our post on preparing for your MTD final declaration.

What the Final Declaration Process Actually Looks Like

The final declaration is completed through your MTD-compatible software - the same software you use to file your quarterly updates. Your software will pull in the quarterly figures you have already submitted and present them alongside sections for the additional income types, allowances, and adjustments covered above.

You review the figures, add anything that was not in your quarterly updates, confirm your allowances, and submit. HMRC then calculates your tax for the year and either shows you what you owe or confirms a refund. Payment for any tax owed is due by 31 January 2028 - the same date as the final declaration itself.

For a step-by-step walkthrough of how to complete it, see our post how to complete your MTD final declaration.

Eight Months Is More Than Enough - If You Use It

The gap between the Q4 deadline (7 May 2027) and the final declaration deadline (31 January 2028) is not just waiting time. It is the window in which you can do everything you need to do without rushing.

Use it to:

• Collect your P60 and any other employment documents after 5 April 2027
• Review your quarterly update figures for the full year and check for anything that needs correcting
• Work out your mixed-use expense adjustments
• Decide how to handle any losses
• Gather dividend and savings interest records
• Set aside money for the tax payment due in January

Doing this gradually - a little at a time over the summer and autumn - is far easier than trying to gather eight months of paperwork in the last two weeks of January.

Putting It Together

The MTD final declaration deadline of 31 January 2028 is not an afterthought. It is the step that actually closes the tax year. Your quarterly updates gave HMRC a picture of your business income as it happened - but the final declaration is where you add everything else, claim your allowances, confirm your figures, and settle your tax for the year. Filing Q4 by 7 May 2027 is a milestone worth marking, but it is not the finish line. You have eight months from there to gather what you need and complete the final step on time - and that is a generous window if you use it well.