For years, spreadsheets have been the backbone of small business bookkeeping. And it’s easy to see why, because they’re cheap, accessible, and, generally speaking, get the job done.

However, with the arrival of Making Tax Digital, sticking with spreadsheets alone and avoiding MTD software could be your biggest compliance risk.

Because, as of 6 April 2026, MTD for Income Tax applies to self-employed people and landlords with qualifying gross income above £50,000 for the 2024/25 tax year. And the scale of the change is significant, with HMRC estimating that over 860,000 sole traders and landlords need to adapt to digital tax reporting from that date.

In this article, we’ll explore the reasons MTD software is so important, why spreadsheets alone aren’t sufficient anymore, and how to stay compliant in 2026 and beyond.

Why spreadsheets alone are no longer enough

Under the new MTD rules, you can’t keep your accounting figures in Excel and type them into HMRC’s website once a year.

Instead, MTD for income tax requires two key things:

Digital records of your income and expenses, kept throughout the year
Quarterly updates submitted to HMRC through compatible software.

On top of this, at the end of the tax year, you must also use compatible software to make any necessary adjustments, include other taxable income and gains, and submit your tax return by the normal 31 January deadline. This final submission is sometimes referred to as the Final Declaration. This means that a standalone spreadsheet, however well-organised, can’t submit your data to HMRC in the way the rules now require.

This is mostly because the information has to travel digitally, which is where many businesses come unstuck.

The role of MTD bridging software

This doesn’t mean you have to abandon your spreadsheets entirely. Instead, if your records are thorough and you’d rather not switch to a full accounting package, MTD bridging software offers a middle ground.

MTD bridging software connects suitable spreadsheet records to HMRC-compatible services so that the required information can be submitted digitally. This may let you retain much of your existing bookkeeping process, although the spreadsheet, bridging software and digital links must all be set up correctly at the outset. As a result, for methodical business owners with well-kept spreadsheets, it can be effective.

However, the caveat: bridging software only works if your spreadsheet is in good shape. It won’t fix formula errors, spot missing transactions, or organise data. You must avoid these. The bridging software just passes on whatever figures are there, so if your spreadsheet is a mess, the tool will simply submit a mess.

The hidden risks of relying on spreadsheets

Spreadsheets carry risks that can go unnoticed until something goes wrong. And under MTD, with more frequent submissions, those risks are even higher than before.

Here are the main issues we see from Leeds businesses:

Manual errors

Every figure you type by hand has the potential to be incorrect. This is important because a wrong cell or broken formula can throw off your entire submission and land you in hot water with HMRC.

No automation

Spreadsheets can’t pull in bank feeds or categorise expenses automatically, so everything relies on you keeping information accurate and up to date. Some sole traders struggle with this, as do landlords and other eligible business owners.

No deadline reminders

Most bridging tools won’t alert you when a quarterly update is due, so you have to track every deadline yourself. This leads to issues for smaller business owners or sole traders who aren’t used to keeping up with these kinds of official deadlines so frequently.

Any one of these problems can lead to an inaccurate submission, and inaccurate submissions can lead to penalties with HMRC. And when you’re submitting four times a year rather than once, which is the case under MTD, the chances of something going wrong are considerably higher than before.

MTD penalties to be aware of

When it comes to MTD, the penalty system operates on a points-based model, similar to the one already used for VAT.

Here’s how it works:

Every missed quarterly update or Final Declaration deadline is a penalty point.
Once you reach four points, HMRC issues a £200 penalty.
Individual penalty points normally expire after 24 months if you haven’t hit the penalty threshold. Once the threshold has been reached, the points don’t simply expire automatically: the taxpayer must meet the required period of compliance and bring outstanding submissions up to date.
Late payment penalties are separate, starting from day sixteen after the due date and escalating if the tax remains unpaid after thirty days.

To help people get used to the new rules, penalty points won’t be issued during the 2026/27 tax year for quarterly updates submitted within a month of the deadline. However, this grace period doesn’t cover the Final Declaration or payment penalties.

This means that adherence to the deadlines is important, and a badly set-up spreadsheet or an overreliance on spreadsheets might become a roadblock.

How to choose MTD compatible software that suits you

The good news is that you have options when it comes to choosing the right MTD compatible software. Let’s look at two of the most popular.

The first is full cloud accounting software, such as Xero or QuickBooks. These replace your spreadsheet and handle record-keeping and submission in the same place. They also have features like bank feeds, automatic expense categorisation, and reminders. These can all go a long way to reducing the manual workload of spreadsheets and the risk of error.

What’s more, your accountant can log into any of these accounts and support you directly, which, again, improves your chances of getting things right.

The second option is keeping your spreadsheet and pairing it with MTD bridging software. This suits people whose records are already well-organised and who prefer the familiar system of using their spreadsheets. It may have a lower initial software cost, but the total amount will depend on the bridging product, the quality of the records and the amount of checking or professional support required to keep things ticking along.

For most growing businesses in Leeds and beyond, we tend to recommend full accounting software as the safer choice. The automation usually pays for itself in saved time and reduced risk, particularly as MTD for income tax becomes more commonplace, and the demands more frequent.

How to make the MTD software switch

If all of this feels daunting, it doesn’t have to be. Making the move away from spreadsheet dependence is far easier when you approach it methodically and give yourself enough time.

Here are a few sensible steps:

Confirm whether the rules apply to you by checking your qualifying income against the thresholds.
Request a handful of demos to whittle down your software shortlist. This gives you the freedom to choose one that suits your business.
Decide on your MTD software early, whether that’s full accounting products or a spreadsheet plus MTD bridging tool.
Open a dedicated      bank account so your records stay clean and separate from personal spending.
If you have already entered MTD, review your first quarter before its submission deadline and correct any weaknesses in the process. If your mandatory start date is April 2027 or April 2028, carry out a trial quarter in advance.

Above all, don’t leave getting ready until the last minute. The businesses that prepare early find the transition smooth, but the ones that wait may face a stressful challenge when their first deadline looms.

Don’t let spreadsheets be your downfall: get the right MTD software

Spreadsheets have served smaller businesses well for decades, and they still have their place. However, relying on them alone under MTD rules is a risk that could lead to errors, missed deadlines, and penalties.

Whether you move to full accounting software or keep your spreadsheet supported by an MTD bridging tool, the important thing is to act now rather than later.

At UWM, we’ve spent years helping Leeds businesses navigate exactly this kind of change. As such, our specialists can guide you through MTD options and set you up with a system that takes the risk and the stress, out of the process.

And whatever route you choose, the message is simple. Don’t let a spreadsheet you’ve trusted for years become a huge risk to your business. Because a little bit of preparation now might just save you a great deal of trouble down the line.