MTD ITSA Is Coming. Here's What Changes for Your Agency.

If you run a marketing agency, digital agency, or creative agency as a sole trader or partnership, and your total income from self-employment and property is over £50,000 per year, you need to prepare digital records MTD ITSA agency style before April 2026. That is not a suggestion. It is a legal requirement.

Making Tax Digital for Income Tax Self Assessment (MTD ITSA) replaces the old annual tax return system with quarterly digital updates to HMRC. You submit four quarterly summaries during the year, plus one final declaration after year end. No more paper records. No more spreadsheet-only bookkeeping. No more dropping everything in April to scramble through shoeboxes of receipts.

HMRC consulted on this for years. They delayed it twice. It is happening now. If your agency's gross self-employment income exceeds £50,000 in a tax year, you are in scope from April 2026. If it exceeds £30,000, you are in scope from April 2027. Below £30,000, you can volunteer but are not mandated.

This article walks you through exactly what you need to do, what software you need, and how to avoid the common mistakes agency founders make when transitioning from manual records to fully digital compliance.

Who Exactly Is in Scope for MTD ITSA?

HMRC defines the trigger as "qualifying income" from self-employment and property. For agency founders, that means the gross income your agency generates before deducting expenses. Not your profit. Not your personal drawings. The top-line revenue.

Here is the timeline:

  • April 2026: Mandatory for sole traders and partnerships with total qualifying income over £50,000 per year.
  • April 2027: Mandatory for those with qualifying income over £30,000 per year.
  • April 2028 (tentative): Expected extension to those over £10,000.

If you are a sole trader web designer turning over £65,000, you are in scope from April 2026. If you run a 12-person digital agency billing £800k per year as a limited company, you are not in scope for MTD ITSA at all, limited companies already use MTD for VAT and will eventually use MTD for Corporation Tax (separate timeline, not yet confirmed).

But many agency founders operate as sole traders or partnerships in their early years. If that describes you, read carefully. If you are incorporated, this article still matters, your subcontractors and freelancers may be sole traders who need your help to understand the rules.

What Digital Records Must You Keep?

HMRC is specific about this. You must maintain digital records of all income and expenses in compatible software. You cannot use paper records or unstructured spreadsheets as your primary record-keeping method. You can use spreadsheets, but they must be linked to MTD-compatible software through an API bridge.

The records you must keep digitally include:

  • All income received, by date and source. For agencies, that means each client payment, retainer invoice, and project fee.
  • All business expenses, by date and category. That includes software subscriptions like Xero or QuickBooks, freelancer payments, travel costs, office rent, equipment purchases, and professional fees.
  • Personal drawings or amounts taken for personal use if you run a sole trader agency.
  • Any adjustments or corrections to previous submissions.

You must also keep the original source documents, invoices, receipts, bank statements, but those can be digital copies. HMRC accepts scanned receipts and digital invoices. You do not need to keep paper originals, though many accountants recommend keeping them for six years as a backup.

Our ICAEW qualified team recommends using Dext or AutoEntry for receipt capture. Both integrate with the main accounting platforms and let you photograph receipts on your phone. The software extracts the key data and categorises it. No more lost receipts from that client lunch in Shoreditch.

Which Software Is MTD ITSA Compatible?

Not all accounting software is MTD ITSA compatible. HMRC maintains a list of recognised software providers. As of early 2025, the major platforms that have confirmed MTD ITSA compatibility include:

  • Xero, already MTD VAT compatible. Their MTD ITSA module is in testing. Most agency founders we work with use Xero already.
  • QuickBooks, similar timeline. Full MTD ITSA functionality expected by late 2025.
  • FreeAgent, popular with sole traders and small agencies. MTD ITSA ready.
  • Sage, available for both desktop and cloud versions.
  • IRIS, used by many accountancy firms for practice-side compliance.

If you currently use spreadsheets only, you have two options. Option one: migrate to cloud accounting software now. Option two: keep using spreadsheets but bridge them to HMRC via MTD-compatible spreadsheet software. Most agency founders find option one simpler because it automates the quarterly submissions and reduces admin time.

We do not recommend waiting until March 2026 to choose your software. Migrating your historical records takes time. Testing the quarterly submission process takes time. And if you get it wrong in the first quarter, you face late submission penalties from day one.

How the Quarterly Submission Process Works

Under MTD ITSA, your tax year still runs 6 April to 5 April. But instead of filing one return by 31 January, you submit four quarterly updates and one final declaration.

The quarterly submission deadlines are:

  • Quarter 1 (6 April to 5 July): Submit by 5 August.
  • Quarter 2 (6 July to 5 October): Submit by 5 November.
  • Quarter 3 (6 October to 5 January): Submit by 5 February.
  • Quarter 4 (6 January to 5 April): Submit by 5 May.

After the fourth quarter, you submit a final declaration by 31 January the following year. That declaration confirms your total income and expenses for the year, accounts for any adjustments, and calculates your final tax bill.

Here is the practical reality for agency founders. If you bill clients monthly on retainer, your income is predictable. The quarterly update takes 15 minutes. If you run a project-based agency with irregular cash flow, you need to reconcile invoices and payments more carefully each quarter. But the process is still faster than an annual return because you are working with current data, not trying to reconstruct 12 months of transactions from memory.

A 12-person digital agency billing £800k per year as a sole trader would submit four quarterly summaries showing roughly £200k of income each quarter. HMRC uses those updates to calculate a provisional tax position. You can choose to pay tax quarterly based on those updates, or stick with the existing twice-yearly payments on account. Your choice.

Penalties for Late or Incorrect Submissions

HMRC is introducing a new points-based penalty system for MTD ITSA. You receive one penalty point for each late submission. Accumulate enough points, and you face a financial penalty. The points reset after a period of compliant submissions.

For quarterly updates, the penalty threshold is typically 2 points for annual filers. For the final declaration, it is 1 point. Each point carries a £200 penalty. So two late quarterly updates could cost you £400 before you even file the final return.

Incorrect submissions also carry risk. If HMRC finds you deliberately understated income or overstated expenses, the penalties are higher. But honest mistakes caught early through quarterly updates are less likely to trigger penalties than errors buried in an annual return filed 10 months after year end.

The key takeaway: do not treat quarterly updates as rough estimates. They must be accurate to the best of your knowledge based on the digital records you hold. If you discover an error in a later quarter, you can correct it in the next update or in the final declaration.

What Agency Founders Should Do Between Now and April 2026

Step 1: Assess Whether You Are in Scope

Calculate your gross self-employment income for the current tax year. If it exceeds £50,000, you are mandated from April 2026. If it is between £30,000 and £50,000, you have until April 2027. If it is below £30,000, you can volunteer or wait.

Step 2: Choose Your Software and Migrate

If you do not already use cloud accounting software, choose one now. Xero and FreeAgent are the most common choices for agency founders. Both offer free trials. Set up your chart of accounts to match your agency's income streams, retainer income, project income, expense categories for freelancers, software, travel, and office costs.

Migrate your historical records for the current tax year. If you start using the software from April 2025, you have a full year to test the quarterly submission process before it becomes mandatory in April 2026. That is the smart play.

Step 3: Connect Your Bank Feeds

Cloud accounting software connects directly to your business bank account. Transactions flow in automatically. You categorise them once, and the software remembers. This eliminates manual data entry and reduces errors.

If you use a personal bank account for business transactions (common among sole trader agency founders), consider opening a separate business bank account now. It simplifies categorisation and makes quarterly submissions faster. Starling, Tide, and Monzo all offer free business accounts that integrate with Xero and QuickBooks.

Step 4: Set Up Receipt Capture

Install Dext or AutoEntry on your phone. Photograph every business receipt as you receive it. The software extracts the date, amount, and supplier. You assign the category. Done.

This habit alone saves agency founders hours of admin time each quarter. No more hunting through wallets, glove compartments, or email inboxes for that receipt from the client meeting in Bristol Harbourside.

Step 5: Run a Test Quarter

In Q1 2025/26 (July 2025), submit a voluntary quarterly update through your software. See how the process works. Check that the numbers match your bank statements. Identify any gaps in your record-keeping. Fix them before the mandatory deadline.

Most accounting software providers offer guided walkthroughs for the first submission. Take advantage of those.

Common Mistakes Agency Founders Make

Mistake 1: Confusing MTD ITSA with MTD VAT. They are separate systems. If you are VAT registered and already submit MTD VAT returns, that does not exempt you from MTD ITSA. Different software modules, different submission schedules, different penalties.

Mistake 2: Thinking spreadsheets are fine. They are not, unless bridged through compatible software. HMRC requires digital records, not digital copies of paper records. A spreadsheet saved as a PDF is not a digital record. A spreadsheet linked to an MTD-compatible API is.

Mistake 3: Ignoring the quarterly deadlines. The first quarterly submission deadline under mandatory MTD ITSA is 5 August 2026. If you miss it, you get a penalty point. If you miss two, you get a £200 fine. Set calendar reminders now.

Mistake 4: Not reconciling bank accounts monthly. Quarterly submissions are easier if your bank feeds are reconciled every month. Letting transactions pile up for three months creates a scramble at submission time. Reconcile weekly if you can. Monthly at minimum.

How Your Accountant Can Help

If you work with an ICAEW qualified accountant like Agency Founder Finance, they handle the technical compliance. You handle the record-keeping. Under MTD ITSA, that division of labour becomes even more important.

Your accountant can:

  • Confirm whether you are in scope for MTD ITSA based on your specific income mix.
  • Recommend the right software for your agency size and complexity.
  • Set up your chart of accounts to match your income streams and expense categories.
  • Run the quarterly submissions on your behalf if you grant them access to your software.
  • Advise on whether to pay tax quarterly or stick with payments on account.

If your accountant has not raised MTD ITSA with you yet, ask them directly. Some firms are slower to adapt than others. You want someone who is already testing the quarterly submission process, not someone who will figure it out in March 2026.

For more on how we support agency founders with digital compliance, see our services page. If you work with a marketing agency specifically, our marketing agency services page covers the sector-specific considerations.

What About Limited Company Agency Founders?

If your agency is a limited company, MTD ITSA does not apply to you directly. You file corporation tax returns, not self assessment. But MTD for Corporation Tax is coming. HMRC has not confirmed a start date, but expect it within the next 3-5 years.

In the meantime, if you pay yourself through dividends and a salary, your personal self assessment may still be in scope for MTD ITSA if you have significant self-employment income outside the company. Most agency founders do not. But if you also run a freelance side business or have property income, check your total qualifying income.

For incorporated agency founders, the smart move is to already use cloud accounting software for your company records. Xero, QuickBooks, and FreeAgent all handle corporation tax compliance. When MTD for Corporation Tax arrives, you will already be compliant.

Start Now. Do Not Wait.

April 2026 sounds distant. It is not. That is one full tax year from now. If you start preparing today, you have time to choose software, migrate records, test the process, and fix problems before the first mandatory deadline.

If you wait until January 2026, you are rushing. And rushing leads to mistakes. Mistakes lead to penalties. Penalties cost money you would rather spend on growing your agency.

To prepare digital records MTD ITSA agency founders need to act now. Set up your software. Connect your bank feeds. Start capturing receipts digitally. Run a test quarter. By the time the 2026 deadline arrives, you will wonder why you ever did it the old way.

If you need guidance specific to your agency's situation, contact us. Our ICAEW qualified team works exclusively with agency founders. We know the software, the deadlines, and the practical realities of running a client services business while staying compliant.

For more on digital record-keeping and compliance, browse our tax and compliance blog or our Making Tax Digital articles.