5 MTD Mistakes Landlords Are Already Making, and How to Fix Them

The most common Making Tax Digital mistake landlords make is testing the £50,000 entry threshold against rental profit rather than gross rents, which is why thousands of property investors believe they are outside a regime they joined on 6 April 2026. Making Tax Digital for Income Tax has been live for five months, the first quarterly update deadline of 7 August 2026 has passed, and the errors emerging are practical rather than technical. Most stem from applying self-assessment habits to a system that no longer works that way. Blue Tick Accountants, a Guildford-based UK tax advisory and accountancy practice, reviews property portfolios for MTD compliance across the UK. This article sets out the five mistakes appearing most often in the first year of Making Tax Digital landlords 2026 rules, what each one costs, and how to correct it before the 7 November 2026 deadline.

Key Takeaways

• Making Tax Digital for Income Tax applies to landlords with qualifying income above £50,000 from 6 April 2026, falling to £30,000 from April 2027 and £20,000 from April 2028.
• Qualifying income is gross rental and self-employment income combined, measured before any expenses are deducted, so a landlord with £55,000 of rents and a £12,000 profit is in scope.
• Quarterly update deadlines for the 2026/27 tax year are 7 August 2026, 7 November 2026, 7 February 2027 and 7 May 2027, with a final declaration due by 31 January 2028.
• A UK property business, an overseas property business and any sole trade each require their own separate quarterly update.
• The Section 24 finance cost tax credit of 20% is claimed at the final declaration, not in quarterly updates, so quarterly figures will overstate taxable profit.
• Late quarterly updates carry no penalty points during the 2026/27 soft landing year, but from 2027/28 each one earns a point, with a £200 penalty once four accumulate.

Mistake 1: Testing the £50,000 threshold against profit instead of gross rent

The £50,000 MTD threshold is measured on qualifying income, which is gross rental receipts and gross self-employment turnover added together before a single expense is deducted. Mortgage interest, letting agent fees, repairs and insurance are irrelevant to the test.

This catches leveraged landlords hardest. A portfolio generating £62,000 of annual rent with £48,000 of costs produces a £14,000 profit, an income tax bill of a few thousand pounds, and full MTD obligations from 6 April 2026. Combining income sources is the second trap: a landlord with £34,000 of rents and £21,000 of consultancy turnover has £55,000 of qualifying income and is in scope, even though neither source alone would breach the threshold.

HMRC identified the first tranche of entrants from 2024/25 self-assessment returns and wrote to those affected, but letters go astray. Check the return directly. Add the gross property income and gross trading turnover boxes, and if the total exceeds £50,000, the obligation started in April 2026 whether or not a letter arrived.

Mistake 2: Filing one update for a portfolio that is legally several businesses

Every separate income source needs its own quarterly update, so a landlord with UK rentals, a Spanish apartment and a small consultancy files three sets of updates rather than one.

For MTD purposes a UK property business and an overseas property business are distinct, because they are taxed under different rules and losses cannot be pooled between them. Furnished holiday lettings no longer form a separate category following their abolition in April 2025, so UK holiday lets now sit inside the ordinary UK property business.

Jointly owned property adds a further layer. A landlord holding property jointly reports only their share of income, and HMRC permits joint owners to report income alone in quarterly updates, adding the expense position at the final declaration. That easement cuts quarterly work considerably for couples holding property together.

For the full picture of how to set up and run MTD across a portfolio, see our guide to Making Tax Digital for landlords.

Mistake 3: Keeping records in a spreadsheet with nothing to submit them

A spreadsheet is a legitimate way to keep digital tax records property income requires, but only where bridging software connects it to HMRC, because a spreadsheet alone cannot file a quarterly update.

The MTD ITSA landlord obligation has two halves: records must be created and preserved digitally, and updates must reach HMRC through compatible software. Retyping figures from a spreadsheet into a portal breaks the digital link and does not satisfy the legislation.

Each transaction must also be recorded individually with its date, amount and category. A single monthly entry reading "rents £4,800" is not a digital record of five tenancies. Receipts and invoices themselves may still be kept on paper, which surprises many landlords who assumed everything had to be scanned. Property-specific packages and bridging tools both work, provided the software appears on HMRC's list of compatible products and the landlord, or their agent, holds a valid authorisation to file.

Mistake 4: Expecting quarterly updates to show the real tax position

Quarterly updates are unadjusted summaries of income and expenses, not tax computations, so the estimated tax figure produced after each submission will be wrong for almost every leveraged landlord.

Finance costs are the reason. Since the Section 24 restriction, mortgage interest is not deductible from rental profit but instead generates a basic rate tax credit of 20%, applied at the final declaration. Quarterly updates therefore report profit before any relief for interest, inflating the apparent liability throughout the year.

Capital allowances, the property income allowance, losses brought forward and rent-a-room relief are handled the same way, all at final declaration stage. The practical consequence is a budgeting one: a landlord paying £19,000 of mortgage interest sees quarterly estimates roughly £3,800 higher than the eventual liability, so treating those estimates as the amount to set aside overstates the reserve required.

Mistake 5: Assuming a missed quarter is a minor administrative slip

HMRC has applied a soft landing to the first twelve months, so late quarterly updates in 2026/27 carry no penalty points. From 2027/28 each one earns a point, and a £200 penalty falls due on reaching four, which a landlord with a single property business accumulates in exactly one tax year of missed deadlines.

Points expire only after a period of compliance, so a landlord who misses two quarters once the soft landing ends carries those points forward, and landlords running three separate businesses face separate points totals for each.

Late payment penalties operate separately and bite harder. Tax unpaid 15 days after the due date attracts a 3% charge, a further 3% applies at 30 days, and penalties accrue at 10% annualised from day 31.

Correcting a missed quarter is straightforward: submit the update late, because a cumulative update at the next quarter does not remove the point already incurred. Anyone who has missed 7 August 2026 should file before 7 November 2026 compounds the problem.

Frequently Asked Questions

Do I need to use Making Tax Digital if I only own one rental property?

Yes, if the gross rent from that property, added to any self-employment turnover, exceeds £50,000 in the relevant year. A single high-value London property letting for £55,000 a year brings the landlord into Making Tax Digital for Income Tax from 6 April 2026, regardless of how small the profit is after mortgage interest and costs.

What are the quarterly update deadlines for landlords in 2026/27?

Quarterly updates for the 2026/27 tax year are due by 7 August 2026, 7 November 2026, 7 February 2027 and 7 May 2027, covering the standard quarters ending 5 July, 5 October, 5 January and 5 April. A final declaration replacing the self-assessment return must then be submitted by 31 January 2028.

Can I still use a spreadsheet for my rental records under MTD?

Yes. Spreadsheets remain acceptable for keeping digital records of property income, provided each transaction is recorded individually and bridging software transmits the quarterly totals to HMRC. Manually retyping figures into an HMRC portal is not permitted, because the legislation requires an unbroken digital link between the record and the submission.

How does Section 24 mortgage interest relief work under quarterly reporting?

Mortgage interest is not deducted in quarterly updates. It is reported separately and converted into a 20% basic rate tax credit at the final declaration stage. Quarterly estimates therefore overstate the tax due for any mortgaged landlord, and a landlord paying £19,000 of interest sees roughly £3,800 of relief arrive only at the end of the year.

What happens if I miss a quarterly update deadline?

For 2026/27 no penalty point is issued for a late quarterly update, because HMRC has applied a soft landing to the first twelve months of the regime. From 2027/28 a missed update generates one point, with a £200 penalty once four points accumulate. The update is still legally required, and the final declaration carries points in the normal way.

When will landlords earning under £50,000 join MTD?

Landlords with qualifying income above £30,000 join Making Tax Digital for Income Tax from April 2027, and those above £20,000 join from April 2028. Landlords with qualifying income below £20,000 remain outside the regime for now and continue to file an annual self-assessment return in the usual way.

How Blue Tick Can Help

Most of these errors are cheap to fix in September and expensive to fix in January. Blue Tick Accountants checks whether your portfolio genuinely falls within the threshold, maps each property and trade to the correct business, sets up compatible software with agent authorisation in place, and handles the quarterly updates and final declaration so the Section 24 credit and capital allowances are claimed in full. Head to our website and book a meeting now.

Conclusion

Making Tax Digital has not changed what landlords owe, only how and when they report it, and every mistake above comes from carrying annual self-assessment thinking into a quarterly system. Check the threshold against gross rents, split the portfolio into its correct businesses, get compatible software connected, and treat quarterly estimates as provisional. The 7 November 2026 deadline is the next opportunity to get the process right, and correcting the record now is far simpler than unwinding four quarters of errors at the final declaration.

About the Author

This guide was written by Leon, founder of Blue Tick Accountants, a Guildford-based UK tax advisory and accountancy practice that helps landlords, limited company owners and the self-employed across the UK. Leon advises property investors on rental profit computations, Section 24, and Making Tax Digital compliance. It was last reviewed for the 2026/27 tax year.

This article is intended for general informational purposes only and does not constitute tax, legal, or financial advice. Tax rules are subject to change and their application will depend on your individual circumstances. You should always seek advice from a qualified professional before taking action. Blue Tick Accountants accepts no liability for decisions made on the basis of this content.

Related reading: Quarterly MTD Returns for Landlords: What You Actually Need to Submit.

Related reading: MTD for Property Income: What Records Must You Keep Digitally?.