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From 2026-27 onwards, you correct the digital record in your MTD software and the fix reaches HMRC in your next quarterly update. Mistakes found after the fourth update are fixed by resending it before your tax return.
Making Tax Digital for Income Tax (MTD) was built with corrections in mind. Each quarterly update is a running total from 6 April to the end of the period, not a separate report for three months, so the next update carries the corrected totals. The rules come from regulation 17 of the Income Tax (Digital Obligations) Regulations 2026 and GOV.UK guidance, as checked on 16 October 2026.
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When you find it decides what you do
| When you spot the mistake | What to do | The corrected figure must reach HMRC by |
|---|---|---|
| After update 1, 2 or 3 | Correct the digital record; the next update carries it | Your next quarterly update deadline |
| After update 4, before the tax return | Correct the record and resend update 4, or adjust the category total in your software and reflect it in your records | The tax return deadline, 31 January |
| After the tax return | Amend the tax return in your MTD software | Within 12 months of the submission deadline |
The regulations also say a wrong or missing digital record must be corrected as soon as possible after you find it, so do not leave it until the next deadline. If a business stopped during the year, a mistake in the update for the period in which it stopped follows the same tax return deadline as update 4.
What counts as a mistake
GOV.UK describes two kinds: a digital record made wrongly, and income or costs you forgot to record. In practice, for a tradesperson or landlord that usually means:
- a bank-feed transaction pulled in twice, or a supplier refund recorded as income
- a cost recorded as income, or income recorded as a cost
- a personal purchase on the business card
- a cash job, or a tenant's cash rent, that did not go through the bank
- a materials invoice paid from a personal card, so it did not show in the business bank feed
To fix it, you change, delete or create a digital record. If you use one software product for everything, you make the change there. If your records live in a spreadsheet with separate bridging software, correct the spreadsheet and keep the digital link; once a record has gone to HMRC it must not be retyped or copied and pasted into other software.
A worked example
A roofer sends the first update of 2027-28, for 6 April to 5 July 2027. In August he spots two errors: a £1,450 scaffold hire invoice came through the bank feed twice, and a £600 cash repair job was not recorded.
| Income | Expenses | |
|---|---|---|
| Update 1 as sent (6 April to 5 July 2027) | £18,400 | £6,820 |
| Update 1 as it should have been | £19,000 | £5,370 |
| Update 2 sent by 7 November 2027 (6 April to 5 October 2027) | £40,500 | £11,470 |
He deletes the duplicate, adds the cash job, and carries on. The second update includes £21,500 of new income and £6,100 of new costs on top of the corrected first-quarter figures. He does not resend update 1: the running totals in update 2 put HMRC's figures right. This is an example only.
Corrections are not adjustments
Some year-end changes are not mistakes. GOV.UK lists adjustments made after the fourth update and before the tax return, such as taking out the private share of a phone bill, claiming capital allowances, and accounting adjustments if you do not use the cash basis. Its digital records guidance adds simplified expenses, such as the flat mileage rate, which are also dealt with as an adjustment before you finalise your tax position. You do not need to make these before a quarterly update, so leaving them out of an update is not an error to correct.
What this means for you
A mistake in a quarterly update is not a crisis. Quarterly updates are summaries, not tax returns, and tax is worked out from your tax return. What matters is that the digital records are right before the next update, and that everything is finalised before you file. If someone else keeps your books, an authorised agent can make the correction for you. Before you submit, also check what HMRC has added to your tax return itself, such as CIS deductions from contractors or wages from a job, because GOV.UK says you must check that information too.
Steps to correct a quarterly update
- Find the record that is wrong or missing, and note what the right figure should be.
- Correct it where the record was made: change, delete or add the digital record.
- If you use a spreadsheet and bridging software, make sure the corrected cells are still digitally linked.
- Check the running totals in your software before the next update, then send it by the deadline.
- If update 4 has already gone, resend it with the corrected records before you make year-end adjustments and submit your tax return.
- If the tax return has gone, amend it in your MTD software within 12 months of the 31 January deadline.
The free MTD check shows when MTD starts for you, and the trades section and landlord section cover keeping records right through the year.
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Questions people ask
Do I need to resend a quarterly update that had a mistake in it?
Usually not. Each update covers the tax year so far, so once you correct the digital record, your next update carries the right totals. The exception is the fourth update, which you may need to resend before your tax return.
How quickly do I have to fix a mistake?
The 2026 regulations say a wrong or missing digital record must be corrected as soon as possible. The corrected figures must reach HMRC by your next quarterly update deadline, or by the tax return deadline if the mistake was in the fourth update or in the update for the period in which a business stopped.
Is claiming my mileage or capital allowances at the year end a correction?
No. Those are adjustments, made after the fourth update and before the tax return. GOV.UK says you do not need to make tax or accounting adjustments before sending a quarterly update.
I keep my records in a spreadsheet. Where do I make the correction?
In the spreadsheet. GOV.UK says to correct the record where it was created and then digitally link it to your bridging software, rather than retyping figures.
What if I find the mistake after I have filed my tax return?
Change the tax return using your MTD software. GOV.UK says you can make a change within 12 months of the submission deadline.
Sources
- Use Making Tax Digital for Income Tax: Create digital records, correcting your digital records (GOV.UK)
- Use Making Tax Digital for Income Tax: Send quarterly updates (GOV.UK)
- Use Making Tax Digital for Income Tax: Adjust your self-employment and property income (GOV.UK)
- Use Making Tax Digital for Income Tax: Submit your tax return (GOV.UK)
- The Income Tax (Digital Obligations) Regulations 2026, SI 2026/336, regulations 16 and 17 (legislation.gov.uk)
This is general information to help you understand the rules. It isn't tailored to your circumstances, so check your own position before acting on it.
Righto Tax is a trading name of NJG Consultancy Ltd, registered in England and Wales, company number 16095900. Registered office: Jubilee House, East Beach, Lytham St Annes, FY8 5FT.
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- Use the free Making Tax Digital checker to see your own start date and deadlines.
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