MTD Bridging Software: What It Is and Do You Need It

If you have been keeping your books on spreadsheets and are wondering how to comply with MTD without changing your entire system, you have probably heard about bridging software. It sounds like a simple solution — keep your spreadsheet, just add a bridge to HMRC. But is it really the best approach? Here is what you need to know.

What Is Bridging Software?

Bridging software is a tool that sits between your spreadsheet and HMRC's systems. It takes the figures from your spreadsheet and submits them to HMRC in the format required by MTD.

Think of it as a translator. Your spreadsheet speaks one language (rows and columns of numbers), and HMRC's API speaks another (structured digital data). Bridging software converts one into the other.

With bridging software, you continue keeping your records in your spreadsheet. When it is time to submit a quarterly update, the bridging software reads the relevant figures from your spreadsheet and sends them to HMRC.

How Bridging Software Works

The typical process is:

1. You maintain your income and expenses in a spreadsheet, following a specific format required by the bridging software
2. At the end of each quarter, you open the bridging software
3. The software reads the figures from designated cells in your spreadsheet
4. You review the figures and confirm they are correct
5. The software submits the data to HMRC via their API
6. You receive a confirmation of submission

Some bridging tools work as Excel or Google Sheets add-ons, while others are standalone applications that import data from your spreadsheet file.

The Digital Links Requirement

One important rule under MTD is that there must be digital links between all parts of your record-keeping system. This means no manual copying and pasting of figures between spreadsheets or from a spreadsheet into submission software.

If you keep your records in one spreadsheet and your submission summary in another, the two must be linked by formulas — not by you manually typing numbers from one into the other.

Bridging software must read directly from your records spreadsheet. You cannot total up your figures separately and type them into the bridging tool.

This digital links requirement is one of the reasons bridging software can be more complicated than it first appears.

Bridging Software vs Full MTD Software

Here is how the two approaches compare:

| Feature | Bridging Software | Full MTD Software | |---------|------------------|-------------------| | Record keeping | Your spreadsheet | Built-in digital records | | Bank feeds | No | Yes — automatic import | | AI categorisation | No | Yes (in tools like Accounted) | | Receipt capture | No | Yes — photo or WhatsApp | | Tax estimates | Manual calculation | Automatic | | Quarterly submission | Manual trigger | Automatic or one-click | | Digital links | You must maintain them | Built in | | Learning curve | Low (keep your spreadsheet) | Moderate (new system) | | Ongoing effort | High (manual everything) | Low (automated) | | Error risk | Higher | Lower | | Cost | Often free or cheap | Subscription fee |

When Bridging Software Makes Sense

Bridging software can be a reasonable choice if:

• You have a well-organised, established spreadsheet system that you are comfortable with
• Your business is simple — one income source, straightforward expenses
• You are confident maintaining digital links within your spreadsheet
• You are comfortable with manual data entry and do not mind the ongoing effort
• You want to minimise costs and your spreadsheet system is working well
• You see MTD as a temporary compliance requirement rather than an opportunity to improve your bookkeeping

When Full MTD Software Is Better

Full MTD software is the better choice if:

• You want to reduce the time you spend on bookkeeping
• You have many transactions and manual entry is burdensome
• You want automatic bank feeds to capture transactions without effort
• You value real-time tax estimates and financial insights
• You want receipt capture via your phone
• You are worried about making errors in your spreadsheet
• You want your accountant to have easy access to your records
• You see MTD as an opportunity to modernise your financial management

For most sole traders, full MTD software like Accounted is the better long-term investment. The time saved on manual data entry alone typically exceeds the cost of the software subscription.

The Hidden Costs of Bridging Software

While bridging software is often cheaper in terms of direct cost, it has hidden costs:

Time: You still need to enter every transaction manually into your spreadsheet. For a busy sole trader, this can mean hours each month.

Errors: Manual data entry is error-prone. A mistyped figure, a forgotten transaction, or a broken formula can lead to incorrect submissions.

Maintenance: You need to keep your spreadsheet properly structured, with correct formulas and digital links. If something breaks, you need to fix it yourself.

Limited insights: A spreadsheet does not give you real-time tax estimates, cash flow projections, or the kind of financial insights that modern software provides.

Scalability: As your business grows, a spreadsheet becomes harder to manage. Eventually, you will likely outgrow it and need to migrate to proper software anyway.

Making the Transition from Spreadsheets

If you decide to move from spreadsheets to full MTD software, the transition does not need to be painful:

1. Choose your software — look for one that can import historical data from spreadsheets
2. Set up your accounts — create your income and expense categories
3. Connect your bank — this is usually the biggest time-saver
4. Import your opening balances — bring across your year-to-date figures
5. Run both systems in parallel for a month — check that the software captures everything your spreadsheet does
6. Switch over — once you are confident, make the software your primary system

Accounted can import data from spreadsheets and connects to all major UK banks, making the transition straightforward.

Our Recommendation

If you are starting fresh with MTD, skip bridging software and go straight to full MTD software. The initial learning curve is modest, and the time savings over the course of a year are substantial.

If you already have a well-functioning spreadsheet system and genuinely prefer it, bridging software will get you compliant. But keep in mind that you are adding complexity (digital links, bridging tool setup) to maintain a system that requires more manual effort than the alternative.

The question is not just "what is the cheapest way to comply with MTD?" but "what is the smartest way to manage my business finances?" For most sole traders, the answer is software that automates as much as possible.

Penny, our AI bookkeeper, categorises your expenses automatically and flags anything that looks wrong. Try it free for 14 days.