MTD Under the Threshold: Are You Actually Safe?
Think you're exempt from Making Tax Digital because your income is under £50,000? The threshold rules are more complicated than HMRC lets on. Read this first.
If your turnover sits comfortably below £50,000, you have probably told yourself that Making Tax Digital for small business is someone else's problem. That assumption could cost you more than you think.
The threshold story that HMRC tells is clean and simple: earn under £50,000 and you are exempt until April 2026; earn under £30,000 and you are exempt until April 2027. What the press releases do not headline is the part where those thresholds are based on gross income, calculated in ways that catch people out, and where voluntary early adoption carries its own implications. Before you file this away under "not my problem", spend ten minutes here.
- The MTD threshold is based on gross trading income, not profit. A plumber turning over £32,000 with £18,000 in expenses is not automatically exempt.
- If you have multiple income sources, HMRC combines them. A part-time electrician with a rental property could hit the threshold faster than expected.
- Voluntary MTD sign-up is available now and may suit some sole traders below the threshold, but it is not consequence-free.
- The £30,000 threshold giving smaller businesses more time expires in April 2027. That is not far away.
- Going below the threshold after signing up does not automatically release you from MTD obligations without a formal exemption request.
What the Threshold Actually Measures
- MTD Qualifying Income
- The gross income figure HMRC uses to determine whether a sole trader or landlord must comply with Making Tax Digital for Income Tax Self Assessment (MTD for ITSA). It includes total trading income from self-employment plus any property income, before any expenses or allowances are deducted.
This is where many sole traders trip up. The threshold is not about profit. It is not about your take-home. It is about the total money coming in before you subtract a single expense.
Take a self-employed handyman who invoices £48,000 a year. After tools, van costs, insurance, and materials, he clears £29,000. His profit is well below the £30,000 lower threshold. His qualifying income is £48,000, which puts him squarely in the April 2026 cohort for MTD compliance. He is not exempt. He has never been exempt. But if nobody told him to look at gross income rather than net profit, he might not find out until he receives a compliance notice.
HMRC confirmed in its technical guidance that qualifying income means "total gross income from self-employment and property, before any expenses or reliefs are deducted." The legislation underpinning this is the Finance (No. 2) Act 2017, as amended by subsequent statutory instruments that have repeatedly delayed and refined the rollout.
The Multiple Income Sources Trap
The threshold calculation gets more complex if you have more than one source of income. HMRC adds them together.
A part-time electrician earning £22,000 from trade work and £14,000 in rental income from a flat she inherited crosses the £30,000 threshold. She is in scope for April 2027 at the latest, possibly April 2026 if her combined income nudges toward £50,000 in a given tax year. She might think of herself as a small-time operator on both fronts. HMRC's arithmetic disagrees.
Similarly, a freelance graphic designer earning £28,000 from client work who also sells handmade goods online for £5,000 a year has qualifying income of £33,000. The side hustle is not a hobby for threshold purposes; it is income.
This matters because the compliance obligation under Making Tax Digital for small business is not triggered by a single income stream crossing the threshold. It is triggered by the sum total of qualifying sources.
Why Your "Under Threshold" Status Can Change Without Warning
Income fluctuates. A sole trader who earned £27,000 last year might invoice an extra project in spring and clear £31,500 this tax year. HMRC assesses qualifying income based on the previous tax year's self-assessment return to determine whether you are in scope for the following year's MTD obligations.
That lag is both reassuring and dangerous. Reassuring because you are not immediately thrown into MTD mid-year if your income spikes. Dangerous because if you crossed the threshold in 2024/25 and did not register, you could already be non-compliant before the April 2026 mandation date arrives.
HMRC has stated it will write to taxpayers it believes are in scope based on their filed returns. But relying on HMRC to tell you that you owe them compliance is a strategy with a poor track record. The onus is on you to check your own qualifying income.
If you are unsure where you stand, the Self Employed Tax Estimator 2026: Stop Guessing Your Bill can help you get a clearer picture of your income position before HMRC does it for you.
The Voluntary Sign-Up Question
HMRC's MTD for ITSA pilot has been open to voluntary participants since 2022. For some sole traders under the threshold, signing up early sounds prudent. Learn the system before it becomes mandatory. Get ahead of the curve.
But voluntary sign-up is not a consequence-free experiment. Once you are in the MTD system, you are subject to MTD rules. That means quarterly updates, digital record-keeping, and the new penalty regime. If you miss a quarterly submission, the points-based late-filing penalty system applies, regardless of whether you joined voluntarily or were mandated.
The points system works as follows: each missed submission earns one penalty point; when you reach the threshold (four points for quarterly filers), a £200 financial penalty applies. Each subsequent failure adds another £200. Points reset only after a period of full compliance.
For a sole trader earning £25,000 who signed up voluntarily and then had a chaotic quarter, that is a potential £200 penalty for what would previously have been a non-event. Voluntary adoption makes sense if you have the systems in place. It is a trap if you are testing the water without being ready.
What Happens If You Drop Below the Threshold
This is a question few articles answer clearly. Suppose you are mandated into MTD in April 2026 because your 2024/25 income was £52,000. In 2025/26 your income falls to £44,000 due to illness or a slow patch. Are you out?
Not automatically. HMRC's guidance states that once you are in MTD, you remain subject to it unless you actively apply for an exemption or your income falls below the threshold for a sustained period and you cease to meet the criteria. The mechanism for exiting is a formal request, not a self-assessment that your income has dropped.
This asymmetry is worth noting. The system pulls you in based on last year's income. It does not let you out based on this year's income without paperwork. The bureaucratic gravity of MTD flows in one direction.
Exemptions are available on grounds of age, disability, religious objection, or remote location with no reliable broadband. They are not available simply because your income dipped one year. HMRC considers exemptions on a case-by-case basis, and the application process requires evidence.
The Software Cost Nobody Mentions to Sub-Threshold Sole Traders
HMRC chose not to build its own free MTD software. Instead, it mandated that sole traders use HMRC-recognised third-party tools. This is not an accident or an oversight. It is a policy decision that transfers compliance costs to small businesses while creating a guaranteed market for software vendors.
For someone earning £28,000, the cost of MTD-compatible software is not trivial as a percentage of margin. Prices range from roughly £10 per month for basic tools to £50 or more for feature-heavy platforms. Over a year, that is £120 to £600 in additional business overhead, imposed by regulation, on people who were previously filing once a year for free.
For those under the threshold considering voluntary adoption, or for those approaching the threshold and planning ahead, the software choice matters. TapTax: The MTD App Built for Sole Traders is designed specifically for people who want compliance without complexity, at a price point that does not assume you are running a limited company with a finance team.
The investigative point here is that HMRC's decision to mandate private software rather than build a public tool represents a subsidy from sole traders to the software industry. The Federation of Small Businesses has raised this concern repeatedly. It has not changed HMRC's approach.
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The April 2027 Deadline Is Closer Than It Looks
For sole traders and landlords with qualifying income between £30,000 and £50,000, the compliance date is April 2026. For those between £20,000 (the floor HMRC has proposed for a future phase) and £30,000, the date is April 2027.
April 2027 sounds distant. It is roughly two tax years away from the time of writing. But the relevant qualifying income for April 2027 mandation will be determined by your 2025/26 self-assessment return, which you will file by January 2027. By the time you file that return, the compliance obligation will be weeks away. The preparation window is now, not January 2027.
This matters particularly for sole traders in trades where income is volatile: construction, seasonal work, event-based freelancing. A roofer who earns £26,000 in a quiet year might exceed £31,000 in a busy summer. If that income registers in 2025/26, they are in scope for April 2027. They have roughly eighteen months to set up digital record-keeping, choose compliant software, and understand the quarterly submission cycle.
Fifteen minutes of preparation now saves a penalty letter later. If you work in a trade and want a regional picture of how other sole traders in similar positions are approaching this, posts like Making Tax Digital in Taunton: Sole Trader Guide 2026 and Making Tax Digital in Shrewsbury: Sole Trader Guide 2026 cover practical ground for tradespeople.
What to Actually Do If You Are Near the Threshold
If your gross qualifying income is within £10,000 of either threshold, treat yourself as in scope and prepare accordingly. The cost of over-preparing is a few hours and a software subscription. The cost of under-preparing is penalty points, financial penalties, and a compliance notice from HMRC.
Here is a practical checklist:
Check Your Qualifying Income
Add up all gross income from self-employment and property before any deductions. If the number is above £30,000, you are in scope by April 2027. Above £50,000, by April 2026.
Choose Your Software Now
Do not wait until the mandation date to pick a tool. The learning curve for MTD software is shallow but it exists. Starting six months early means any teething problems are resolved before the first real submission deadline.
Understand the Quarterly Calendar
Under MTD for ITSA, you submit four quarterly updates per tax year plus a final declaration. The quarters align with the tax year: April to June, July to September, October to December, and January to March. Missing any of these earns a penalty point.
Do Not Conflate MTD with Your Tax Bill
Quarterly submissions update HMRC on your income and expenses. They do not change when you pay tax. Payment on account and balancing payments remain on the same schedule as before. MTD is a reporting change, not a payment acceleration. If you have been anxious about paying tax four times a year, that anxiety is misplaced. For a clearer view of your likely tax bill regardless of MTD, try the Self Employed Tax Estimator 2026.
If You Have an Accountant, Have the Conversation
MTD does not remove your obligation to maintain digital records. Even if your accountant submits on your behalf, you are still responsible for the underlying data. Do I Need MTD If I Have an Accountant? covers this in detail.
The Bottom Line
At the start of this post, you may have felt safely below the threshold. If nothing else has landed, let this: the threshold is calculated on gross income, it combines multiple income sources, and dipping below it one year does not automatically release you from the system once you are in it.
Making Tax Digital for small business under the threshold is not a binary safe zone. It is a sliding scale with moving parts, and the consequences of misreading it are measured in penalty points and HMRC correspondence. Check your qualifying income today, not in January 2027.
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