How to Correct an MTD Quarterly Update After Submission
Submitted wrong figures in your MTD quarterly update? Here is exactly how to correct an MTD quarterly update, what penalties apply, and what HMRC actually expects.
You hit submit on your MTD quarterly update, closed the laptop, and then found the invoice you forgot to include. Or worse: you realise three weeks later that you categorised £4,000 of materials as income instead of expenses. What happens now?
Correcting an MTD quarterly update is one of the most searched and least clearly explained parts of Making Tax Digital. HMRC's own guidance uses language that assumes you already know the system inside out, which is not especially helpful if you are a plumber trying to fix a spreadsheet error between jobs. This post cuts through that and tells you exactly what to do, in plain English.
- You cannot delete or 'unsend' a submitted MTD quarterly update, but you can correct it by submitting a revised update for the same period.
- HMRC does not issue a penalty purely for correcting an update, provided your final figures are accurate by the time you file your End of Period Statement.
- The correction window is open until you submit your End of Period Statement (EOPS) for that tax year, so you are not permanently stuck with wrong numbers.
- Your MTD software determines how easy the correction process is. Some apps make it one click; others require manual journal entries.
- Errors that affect multiple quarters can be corrected cumulatively, but leaving them until the EOPS deadline adds unnecessary pressure.
Why HMRC's Quarterly Updates Are Not the Final Word
Before panicking, it helps to understand what an MTD quarterly update actually is in legal terms. It is not a tax return. It is not a binding declaration of your final income. Under the Income Tax (Digital Requirements) Regulations 2021, quarterly updates are cumulative snapshots of your income and expenses for each quarter of the tax year. They inform HMRC's in-year tax estimates, but the figure that legally matters is the one you submit through your End of Period Statement for MTD.
That distinction is important because it means a mistake in Quarter 1 does not lock you into a wrong tax liability forever. It does, however, distort your running tax estimate and could cause problems if HMRC uses that estimate to adjust your payments on account.
- MTD Quarterly Update
- A digital submission made four times per year under Making Tax Digital for Income Tax, reporting your cumulative business income and expenses for each quarter. It is not a final tax return. Figures can be corrected up until you file your End of Period Statement for the same tax year.
The Three Most Common Errors Sole Traders Make
Before explaining the fix, it is worth naming the mistakes that most commonly require a correction. Understanding which category your error falls into affects how you correct it.
1. Miscategorised transactions
You recorded a materials purchase as income, or claimed a personal expense as a business cost. This is the most frequent error and, depending on your software, often the easiest to fix.
2. Missing transactions
You forgot to log an invoice or a payment entirely. For a sole trader turning over £60,000, a single missed invoice of £2,500 could meaningfully shift your quarterly estimate and potentially your payments on account calculation.
3. Duplicate entries
You or your bookkeeping app imported a bank transaction twice. This is particularly common when switching between apps mid-year. If you have recently moved platforms, the post How to Switch to MTD Software Without Losing a Day's Work covers how to avoid this in the first place.
How to Correct an MTD Quarterly Update: Step by Step
The mechanism for correcting an MTD quarterly update depends on your software, but the underlying process is consistent across all HMRC-recognised platforms.
Step 1: Identify the exact error and the quarter it affects
Do not guess. Pull up your records for the quarter in question and reconcile them against your bank statements. If you use a spreadsheet bridging tool, check both the spreadsheet and the underlying bank data. If you use a purpose-built MTD app, check the transaction log.
Note whether the error affects income, expenses, or both, and by how much. Write this down. You will need the corrected figures ready before you resubmit.
Step 2: Correct the underlying digital records
HMRC's rules require your digital records to be accurate, not just your submissions. Under Regulation 4 of the Income Tax (Digital Requirements) Regulations 2021, you must keep a digital record of each transaction. Correcting the submission without fixing the underlying record is non-compliant.
In practice, this means:
- In a spreadsheet bridging tool: amend the relevant row and re-categorise the transaction correctly.
- In a dedicated MTD app: edit the transaction directly in the app's ledger. Most apps log the amendment with a timestamp, which is useful if HMRC ever queries it.
- If using bank feed automation: check whether the original import rule caused the error and correct the rule to prevent it recurring.
Step 3: Resubmit the quarterly update for that period
This is where sole traders often get confused. You do not submit a separate "correction form" to HMRC. Instead, you simply submit a new quarterly update for the same period with the corrected figures. HMRC's systems treat the most recent submission for a given period as the current version.
In most MTD software, this looks like navigating back to the relevant quarter, making your amendments, and hitting submit again. The system will accept the revised figures and overwrite the previous submission in HMRC's records.
If your software does not allow you to resubmit a past quarter, that is a significant limitation you need to raise with your provider immediately. It is also worth considering whether your software is genuinely fit for purpose. The HMRC MTD error codes guide can help if you encounter a technical rejection during resubmission.
Step 4: Check the cumulative effect on subsequent quarters
Because MTD quarterly updates are cumulative within a tax year, an error in Quarter 1 that you do not catch until Quarter 3 will have propagated through Quarters 2 and 3 automatically in some software systems, while in others you may need to manually adjust each subsequent quarter.
Check your running totals after correcting Quarter 1 to confirm that Quarters 2 and 3 now reflect accurate cumulative figures. If they do not, repeat the resubmission process for those quarters too.
Step 5: Confirm the correction before submitting your EOPS
Your End of Period Statement is the legally binding submission that crystallises your figures for the tax year. Before you file it, review all four quarters and confirm that the corrected figures flow through correctly. This is your last opportunity to fix any remaining discrepancies without triggering a formal amendment process on a filed return.
For a full walkthrough of the EOPS process, see How to Submit an End of Period Statement for MTD.
What Are the Penalties for Errors in MTD Updates?
HMRC does not issue a penalty simply for correcting a quarterly update. The penalty regime under Finance Act 2021 (and the existing penalty framework under Schedule 24 of Finance Act 2007) focuses on the accuracy of your final tax return, which for MTD purposes is your EOPS combined with your final declaration.
However, there are scenarios where errors become expensive:
Careless inaccuracy: If you file an EOPS with figures you should have known were wrong, HMRC can charge a penalty of up to 30% of the additional tax due. For a sole trader earning £65,000 who under-declared £8,000 of income, that could mean a penalty of several hundred pounds on top of the tax owed.
Deliberate understatement: This carries penalties of up to 70% of additional tax, or 100% in cases involving offshore matters. Worth mentioning only because HMRC's compliance teams do occasionally use quarterly update patterns to flag suspicious under-declarations.
Late filing penalties: These apply to the EOPS and final declaration, not to quarterly updates themselves. Missing the 31 January deadline for your final declaration costs £100 immediately, with further daily penalties after three months.
The practical takeaway: correct errors promptly, before your EOPS. Voluntary corrections made before HMRC opens an enquiry attract the lowest possible penalties, and in most cases no penalty at all.
People also ask
What If Your Software Will Not Let You Resubmit?
This is a real problem that some sole traders encounter, and it deserves a direct answer rather than a diplomatic dodge.
Some MTD bridging tools, particularly older spreadsheet-based solutions, do not have a built-in mechanism for resubmitting a past quarter. They are designed to submit forward, not to revisit previous periods. If you are in this position, your options are:
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Contact your software provider directly. Ask explicitly whether you can resubmit Quarter X with amended figures. Some providers can do this through their back-end portal even if the front-end interface does not surface the option obviously.
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Use HMRC's developer sandbox documentation. This is firmly in the territory of technical users, but HMRC's API for MTD Income Tax does support resubmission of quarterly updates. If your software provider claims it cannot be done, that is a provider limitation, not an HMRC restriction.
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Consider switching software. If your current tool cannot handle basic corrections, it may not be fit for purpose. The changeover is less disruptive than it sounds. See How to Switch to MTD Software Without Losing a Day's Work for a practical guide.
For sole traders who also experience connectivity issues during resubmission, MTD Software Not Connecting to HMRC: Fix It Fast covers the most common technical causes.
Keeping Records of Your Corrections
HMRC has powers to open enquiries into your tax affairs going back four years in standard cases (and up to 20 years in cases of deliberate fraud). That means a correction you make today could theoretically be questioned years from now.
Good practice is to keep a brief written note of:
- Which quarter was corrected and when
- What the original error was
- What the corrected figures are
- Why the error occurred (e.g. "bank feed imported a personal transfer as income")
This is not legally required, but it takes five minutes and could save you hours of explaining yourself to an HMRC compliance officer. Most MTD apps log amendments automatically, but exporting a copy of that log periodically is sensible insurance.
For broader guidance on maintaining clean digital records, How to Keep Digital Records for MTD Without the Chaos is worth bookmarking.
A Quick Scenario: The £4,200 Miscategorisation
To make this concrete: suppose you are a self-employed electrician with annual turnover of around £72,000. In Quarter 2 of the 2026/27 tax year, you accidentally record a £4,200 materials invoice as income rather than an allowable expense. You do not notice until you reconcile your accounts in October.
The impact: your Quarter 2 cumulative income figure is overstated by £4,200, and your cumulative expenses are understated by £4,200 simultaneously. HMRC's in-year estimate now shows you owing significantly more tax than you actually owe. If that estimate feeds into an automatic payment on account adjustment, you could be paying more than necessary for months.
The fix: amend the transaction in your MTD app, re-categorise it as an allowable expense under materials, and resubmit your Quarter 2 update. Check that Quarter 3 (already submitted) has pulled through the corrected cumulative figures. If not, resubmit Quarter 3 with the corrected running totals. Total time: probably 20 minutes with decent software.
For context on what expenses electricians and other tradespeople can legitimately claim, Making Tax Digital for Electricians: The Hidden Admin Cost covers the allowable expense categories in detail.
The Bigger Picture: Why Getting This Right Matters
MTD for Income Tax becomes mandatory for sole traders and landlords with income above £50,000 from April 2026, dropping to £30,000 from April 2027. Early adopters and those on the pilot scheme are already navigating exactly these questions right now.
The correction process described here will become a routine part of self-employed financial management for millions of people over the next few years. HMRC built the resubmission mechanism into the system precisely because they know quarterly submissions will contain errors. The framework assumes imperfection; it just requires you to fix mistakes before they become final.
If you are not yet on MTD and wondering whether this applies to you, Do Freelancers Need Making Tax Digital in 2026? sets out the threshold rules clearly.
You found the forgotten invoice. You spotted the miscategorisation. The question at the top of this post had a straightforward answer: go back into your software, fix the records, and resubmit. The system was designed to let you do exactly that. The only mistake that genuinely costs money is leaving an error uncorrected until after your End of Period Statement is filed, when it becomes an inaccuracy on a legal document rather than a work-in-progress figure in a digital ledger.
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