HMRC says MTD costs £115 a year. Software alone is £216.

If you spent part of this week hunched over a laptop trying to work out why your shiny new tax software wouldn't talk to your HMRC account, you weren't imagining the frustration, and you weren't alone. Yesterday, 7 August 2026, was the first Making Tax Digital quarterly filing deadline in history, and around 864,000 landlords and sole traders were legally required to meet it (HMRC, July 2026). Plenty of them spent longer on the authorisation step than on the figures themselves.

Here's the number that ought to annoy you most. The government's own impact assessment for Making Tax Digital put the ongoing extra cost for a landlord at the £50,000 threshold at £115 a year, on top of a one-off transitional cost of £285 (HMRC Making Tax Digital impact assessment, reported by Property118, June 2026). The cheapest realistic landlord software subscription for someone actually in this year's cohort runs to £216 a year, before you count a single hour of your own time or a penny of extra accountancy fees.

What actually happened on 7 August

Making Tax Digital for Income Tax became compulsory on 6 April 2026 for anyone whose gross income from property and self-employment combined exceeded £50,000 in the 2024-25 tax year. The first quarterly update covered 6 April to 5 July 2026, and it was due by 7 August (GOV.UK, July 2026). It isn't a tax return. It's a summary of income and expenses pushed to HMRC from compatible software, and there are five filings a year in total: four quarterly updates plus a final declaration.

That "five" is where a lot of people came unstuck. Research by business platform Tide, surveying 500 landlords and sole traders in July 2026, found 85% didn't know they'd need to file five times a year, and 31% thought they'd need to make at least eight submissions. The same research found that 25% of those earning above £50,000 still hadn't registered with HMRC a month before the deadline, which works out at roughly 216,000 people (Tide, via Property118, 16 July 2026).

Registration is also two separate jobs, not one. You sign up for Making Tax Digital with HMRC, then you separately authorise your chosen software inside your HMRC account, and if either half is incomplete the submission simply bounces. So if you're still stuck, budget days rather than hours for the plumbing, and don't leave the 7 November update until the first week of November.

The cost HMRC wrote down, and the cost you'll actually pay

Start with the software, because it's the only unavoidable cash cost. Hammock, one of the landlord-specific platforms recognised by HMRC, charges £8 plus VAT a month for one to three properties and £15 plus VAT a month for four to ten (Hammock published pricing, verified May 2026). That's £115.20 and £216 a year respectively.

Look at the smaller of those two figures again. £115.20 is, to within twenty pence, exactly the £115 a year HMRC budgeted for the whole ongoing burden. In other words, the government's estimate covers the cheapest paid software tier and nothing else at all. No time. No accountant. No bank feed that needs unpicking because you paid the plumber on a personal card.

And most landlords in this first wave aren't on that cheapest tier anyway. To clear £50,000 of gross rent you need roughly three properties letting at above the UK average private rent of £1,388 a month (ONS, June 2026), and in practice that usually means four or more doors, which puts you in the £15-plus-VAT band at £216 a year.

Then there's the accountant. More than 200,000 landlords and sole traders were facing accountancy fee increases of up to 10% as Making Tax Digital came in (MoneyWeek, 2026). On a typical small-portfolio fee of around £620, which is what one landlord reported paying in an August 2026 discussion on Property118, a 10% uplift adds £62 a year.

So the honest ongoing cash cost for a four-property landlord in this year's cohort is about £278, not £115, and that's before your own time is valued at anything.

Six working days you don't get paid for

The time cost is the one nobody puts on an invoice. Tide's July 2026 survey found landlords and sole traders expected the new requirements to swallow the equivalent of six full working days over the following twelve months, with 32% expecting to do the work in their own time rather than during working hours. Tide estimated the aggregate hit at £1.5 billion of lost business revenue in the first year.

Six working days is roughly 45 hours, spread across five filings. Call it nine hours a filing, most of it front-loaded into the first year while you learn the categories and get the bank feeds behaving. It's worth being blunt about what you get in return: nothing, at least not directly. As one accountant put it, HMRC does nothing with the quarterly figures until the year end, so you don't pay your tax any earlier and there's no cash-flow benefit to you at all (Simon Misiewicz, quoted by Property118, June 2026).

£278 a year is more than five months of the after-tax profit a higher-rate landlord clears on a genuinely well-yielding Yorkshire buy-to-let.

Put that against actual margins. On the Yorkshire example we ran when the Section 21 backstop lapsed on 31 July, a higher-rate landlord on an 8.7% gross yield was clearing about £52 a month after tax. At £278 a year, digital reporting costs more than five months of that. In the regions where the sums are tighter still, such as the East of England, where even a basic-rate landlord is £222 a month out of pocket, it's simply another line on a loss. So if your portfolio is already running thin after Section 24 stripped out your mortgage interest deduction, treat £278 as a real annual charge against yield, not an administrative footnote.

Three average rentals sit £32 under this year's threshold

Here's the part that catches people out, and it's the reason this matters even if 7 August passed you by entirely. The threshold is measured on gross rent, before any expenses at all. Not profit. Not rent after the agent's cut. The full amount your tenants pay, before mortgage interest, letting fees, insurance, repairs and void council tax come off (HMRC guidance, 2026).

Run the arithmetic at the UK average private rent of £1,388 a month (ONS, June 2026), which is £16,656 a year per property:

Two things follow. First, a three-property landlord letting at anything above the national average is already inside the regime this year, whether or not they've registered. Second, and more important, a plain two-property landlord letting at average rents crosses the £30,000 line comfortably from April 2027, with £3,312 to spare. HMRC identifies who's caught from the previous year's tax return, so your 2025-26 return is the document that decides your April 2027 fate. So if you own two or three properties and have been treating this as a big-portfolio problem, pull that return out this month and look at the gross property income figure, because it's probably already over the line.

If you missed yesterday, you have not been fined

HMRC has confirmed a soft landing: no penalty points will be issued for late quarterly updates during the 2026-27 tax year (HMRC guidance, May 2026). That is a genuine concession, and it's why the tone of some landlord forums this week has been closer to shrugging than panic.

It is also narrower than it looks. The update remains legally required, and all four quarterly updates must be submitted before the final declaration can be filed. Late payment penalties are untouched. The final declaration for 2026-27, due by 31 January 2028, carries the standard Self Assessment penalties from day one: £100 immediately, then daily penalties from three months late. And the grace period expires with the tax year. From 2027-28, every late update earns a penalty point, and four points trigger a £200 charge.

There's a wrinkle worth knowing too. Because updates are cumulative, some landlords are filing provisional figures for the first three quarters and correcting everything at the fourth. That's workable, and several are doing exactly that, but it does mean the software's running tax estimate is fiction until you tidy it up. So don't make a distribution, a repayment or a purchase decision off a quarterly estimate built on placeholder numbers.

What this means for you

Frankly, if you own two or more rental properties and you haven't yet checked your gross rent against £30,000, that's the single most useful hour you'll spend this month. The 2027 threshold is where this stops being a large-portfolio story and starts being a normal-landlord story, and the people who get hurt are the ones who assume a modest portfolio and a thin profit keep them out. Gross rent decides it, and gross rent is a much bigger number than the one you pay tax on.

On the money, the maths points toward paying for decent software and doing the filings yourself rather than handing quarterly work to an accountant. £216 a year for a platform that links to your bank account is defensible. Paying someone £600-plus for the year-end and then a quarterly uplift on top is how a £115 estimate becomes a four-figure one. Most landlords who run these numbers end up self-filing the quarters and keeping the accountant for the final declaration, which is where the judgement actually lives.

What the maths does not support is restructuring to escape this. Limited companies and partnerships sit outside Making Tax Digital for Income Tax for now, and it's tempting to read that as an exit. It isn't. As we set out when we ran the full cost of incorporating an existing portfolio, moving properties into a company can trigger Capital Gains Tax plus the 5% additional-property Stamp Duty surcharge, which is tens of thousands of pounds against an annual saving of a few hundred. If incorporation is right for you, it's right because of Section 24, not because of a quarterly form. Get the £30,000 check done, budget £278 a year, and put the next deadline, 7 November 2026, in the calendar today.