The MTD tax return: your new Self Assessment explained

If you have filed a Self Assessment tax return before, you know the drill. Once a year you gather everything together, tot it up, and send HMRC one summary of your income and tax. For decades that single annual return has been how landlords tell the taxman what they earned.

Making Tax Digital for Income Tax changes how you get there, but the final step is still there and it is called the tax return. It is your new Self Assessment return under a new name, and it is the most familiar part of MTD.

Where the tax return fits

Under MTD for Income Tax, your tax year has three jobs instead of one:

1. Keep digital records of your rental income and expenses as you go.
2. Send HMRC four quarterly updates, which are running totals of how things are looking.
3. Submit one tax return after the tax year ends.

The quarterly updates are deliberately light. They are estimates in progress, not the final word, and they keep HMRC in the loop through the year. The tax return is the third step, and it is the one we are focusing on here.

What the tax return is

The tax return is where the picture gets finished. It is the moment you tell HMRC that this is your complete and final position for the year.

At this stage you confirm your rental figures are correct and add anything the quarterly updates did not capture. That might include:

• any reliefs or allowances you are claiming
• other income, such as employment, savings or dividends
• final adjustments to your figures

Once you have confirmed it all, HMRC works out the tax you owe, just as it always did. The tax return does the job your old Self Assessment return used to do.

The deadline has not moved

The tax return is due by 31 January following the end of the tax year. That is the same date you have always known for Self Assessment.

The UK tax year runs from 6 April to 5 April, so for a tax year ending on 5 April, your tax return is due by the following 31 January. If you have been filing by 31 January for years, your annual finishing line stays where it was. The quarterly updates are new, with their own deadlines through the year, but the big annual date is unchanged.

A word on the quarterly updates

It helps to see where the tax return sits in the year. The standard quarterly periods end on 5 July, 5 October, 5 January and 5 April, with update deadlines of 7 August, 7 November, 7 February and 7 May.

From the 2025-26 tax year onwards, those quarterly updates are cumulative year-to-date totals. Each update shows the running total for the year so far, not just that one quarter on its own, so if you spot a small mistake in an earlier quarter, the next update corrects it. The tax return then sits at the end, after 5 April, pulling it all together so you can finalise everything.

When this applies to you

MTD for Income Tax is being phased in based on your qualifying income, which is your gross rental income plus any self-employment income, before expenses:

• over £50,000: from 6 April 2026
• over £30,000: from 6 April 2027
• over £20,000: from 6 April 2028

If your qualifying income is under £20,000, you are not required to join yet. The tax return only becomes part of your life once you are within MTD.

Why this is more manageable than it sounds

Four quarterly updates plus a tax return can look like the workload has multiplied. In practice the opposite tends to happen.

Under the old system, January was often a scramble: digging out bank statements, hunting for receipts, trying to remember what that payment in June was for. With MTD you have been keeping digital records and sending updates all year, so the figures are already there. The tax return becomes a review-and-confirm exercise rather than a catch-up. You check work you have mostly done, add any last details, and submit.

Plenty of landlords with one property or a small portfolio worry they will now need an accountant. For many, that is not the case. If your affairs are straightforward, this is well within reach to handle yourself, especially with software that keeps your records tidy and files for you. Quarterwise keeps your digital records as you go, files your quarterly updates, and submits your tax return to HMRC, so the year-end is a check-and-confirm rather than a marathon.

This article is general information, not tax advice. Please check with HMRC or a qualified accountant about your own circumstances.