Making Tax Digital MTD for Income Tax Self Assessment (MTD for ITSA) is now live, and the first quarterly update deadline has passed for many practices. Inevitably, some Q1 submissions will contain errors. This guide sets out how practices should identify, correct, and document quarterly update mistakes under HMRC’s Making Tax Digital rules, without triggering unnecessary penalties or client anxiety.
What is Making Tax Digital and why do Q1 corrections matter?
Making Tax Digital is HMRC’s initiative requiring qualifying self-employed individuals and landlords to keep digital records and submit quarterly updates of income and expenses through compatible Making Tax Digital software, rather than filing a single annual return. The first quarterly period typically runs from 6 April to 5 July, with submissions due one month later.
Because this is a new process for both clients and practices, Q1 is where most errors surface: misclassified expenses, transactions logged in the wrong quarter, or figures pulled from incomplete bookkeeping. Getting the correction process right now sets the standard for the rest of the tax year.
How do you correct a Making Tax Digital quarterly update?
Unlike the old Self Assessment return, quarterly updates under MTD are cumulative and provisional. This gives practices some flexibility.
- Amend within the same submission window: If the error is spotted before the next quarterly deadline, most Making Tax Digital software allows a straightforward resubmission of the affected quarter.
- Carry the correction forward: Because quarterly figures are provisional, minor errors can often be adjusted in the next quarter’s update rather than resubmitted separately, provided the discrepancy is properly recorded.
- Reserve major corrections for the Final Declaration: The year-end Final Declaration (which replaced the old End of Period Statement) is where the definitive, accurate figures are confirmed. This is the practice’s safety net for anything not resolved during the year.
What should practices document when correcting making tax digital errors?
Regulators and internal quality processes will expect a clear audit trail. For every correction, practices should record:
- The original figure submitted and the corrected figure
- The reason for the discrepancy (bookkeeping delay, misclassification, missing invoice, and so on)
- The date the correction was identified and actioned
- Client sign-off, where the correction affects taxable income
This documentation matters most where a client’s bookkeeping is being brought up to standard for Making Tax Digital for the first time. For practices still building these habits, our guide on MTD bookkeeping for accounting practices sets out what disciplined day-to-day record-keeping looks like, the kind of process that prevents many Q1-style errors from happening in the first place.
Common causes of Q1 MTD errors
Most Q1 corrections trace back to a small number of recurring issues, which practices flagged in our earlier review of MTD for ITSA common mistakes: incomplete client records at the start of the mandate, confusion over which Making Tax Digital software fields map to which expense categories, and clients missing the concept of quarterly cumulative reporting entirely. Addressing these at source, through client education and clean digital onboarding, is more effective than repeated after-the-fact corrections.
Practices still confirming which clients fall within scope should revisit the current MTD thresholds, as these determine both mandate timing and the volume of correction risk a practice is managing this year.
Should practices use an MTD bridge for corrections?
Get MTD-ready with Befree
Handling Making Tax Digital corrections properly protects both compliance and client trust. If your practice needs support building a robust MTD workflow, from bookkeeping standards through to quarterly filing accuracy, get in touch with the Befree team to discuss how we can help.
For further reading, see our overview on getting ready for Making Tax Digital for Income Tax.