Key dates
Key dates for accountancy practices: October 2026 to November 2027
Dates for a small UK accountancy or bookkeeping practice from October 2026 to December 2027: the Self Assessment and Making Tax Digital deadlines HMRC sets, and the chasing dates our guides count back from them. Deadlines that depend on a client's own year end or confirmation statement date are left out.
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October 2026
Comes round every quarter
Records date for the quarter to 5 October, on an 18-day rule
A records date 18 days after each period ends leaves the practice 15 days before the update is due on the 7th. The same rule gives 23 January, 23 April and 23 July. Who: Practices with clients in MTD for Income Tax
Full guide: How to stop clients sending records late: a records policy for a small practice
Source: Our records policy guide; GOV.UK "Send quarterly updates"
Comes round every year
Paper Self Assessment returns for 2025 to 2026 must reach HMRC
HMRC must receive a paper return by 11:59pm or a late filing penalty applies. It is also the paper cut-off for having a balance under £3,000 collected through the tax code.
Source: GOV.UK "Self Assessment tax returns: Deadlines", read 1 October 2026
November 2026
MTD quarterly update due for 6 April to 5 October 2026
Second update of 2026 to 2027 for clients with qualifying income over £50,000. There are no penalty points this year, but the tax return cannot be submitted until every update has been sent. Who: Clients in MTD for Income Tax since 6 April 2026
Free tool: MTD for Income Tax deadline checker: when each client starts, and the four dates a year
Source: GOV.UK "Send quarterly updates" and "Penalties for Making Tax Digital for Income Tax"
First records request for returns to be filed by 30 December
Counting back 24 days from an internal filing date of Friday 18 December. The reminder follows on 4 December and the final letter on 11 December, leaving 12 days before HMRC's cut-off. Who: Clients with PAYE income who owe less than £3,000
Source: Our 30 December guide and records request letter guide
December 2026
Comes round every year
Last day to file online for tax to be collected through a PAYE code
A 2025 to 2026 return filed online by 11:59pm lets HMRC collect a balance under £3,000 through the 2027 to 2028 tax code in 12 instalments. Filed a day later, the whole balance is due on 31 January. Who: Clients who already pay tax through PAYE
Source: GOV.UK "Self Assessment tax returns: Deadlines" and "Pay your Self Assessment tax bill: Through your tax code", read 1 October 2026
January 2027
Comes round every year
Self Assessment: 2025 to 2026 online return and payment due
Online returns and the tax owed are due by 11:59pm, with any first payment on account for 2026 to 2027. A late return costs £100 at once, and tax still unpaid after 30 days adds 5%.
Free tool: Self Assessment late filing and late payment penalty calculator (2026 rates)
Source: GOV.UK "Self Assessment tax returns: Deadlines" and "Penalties", read 1 October 2026
February 2027
MTD quarterly update due for 6 April 2026 to 5 January 2027
Third update of 2026 to 2027. It falls one week after the Self Assessment deadline, so the records for it are being chased while January returns are still going in. Who: Clients in MTD for Income Tax since 6 April 2026
Source: GOV.UK "Send quarterly updates"
April 2027
MTD for Income Tax starts for qualifying income over £30,000
Clients whose qualifying income for 2025 to 2026 was over £30,000 must use MTD from this date. GOV.UK also says that from April 2027 the points-based penalties apply to everyone who submits a personal Self Assessment return. Who: Sole traders and landlords with qualifying income over £30,000
Source: GOV.UK "Find out if and when you need to use Making Tax Digital for Income Tax" (26 March 2026) and "Penalties for Making Tax Digital for Income Tax" (30 March 2026), read 1 October 2026
May 2027
Final MTD quarterly update for 2026 to 2027 due
Covers 6 April 2026 to 5 April 2027. The tax return for the year, due on 31 January 2028, cannot be submitted until all four updates have been sent. Who: Clients in MTD for Income Tax since 6 April 2026
Free tool: MTD for Income Tax deadline checker: when each client starts, and the four dates a year
Source: GOV.UK "Send quarterly updates" and "Penalties for Making Tax Digital for Income Tax"
July 2027
Comes round every year
Second payment on account for 2026 to 2027 due
Half of the 2025 to 2026 bill again, unless that bill was under £1,000 or more than 80% of the tax owed was collected outside Self Assessment, for example through a PAYE code.
Source: GOV.UK "Understand your Self Assessment tax bill: Payments on account", read 1 October 2026
August 2027
First MTD update of 2027 to 2028: late updates now earn penalty points
For tax years after 2026 to 2027 each missed quarterly update or return deadline earns one point. At 4 points the client pays £200, and another £200 for each deadline missed after that. Who: Every client in MTD for Income Tax
Source: GOV.UK "Penalties for Making Tax Digital for Income Tax" (30 March 2026)
October 2027
Comes round every year
Deadline to register a client who first needs a 2026 to 2027 return
Tell HMRC by this date. Register later and the filing date becomes 31 January 2028 or three months from HMRC's letter if later, but the tax is still due on 31 January 2028 and a penalty can be charged on whatever is unpaid then. Who: New sole traders, landlords and others with untaxed income
Source: GOV.UK "Register for Self Assessment" and "Self Assessment tax returns: Deadlines", read 1 October 2026
November 2027
MTD quarterly update due for 6 April to 5 October 2027
Second update of 2027 to 2028, and the first November deadline for clients who joined on 6 April 2027 with qualifying income over £30,000. A late update now earns a penalty point. Who: Every client in MTD for Income Tax
Free tool: MTD for Income Tax deadline checker: when each client starts, and the four dates a year
Source: GOV.UK "Send quarterly updates" and "Penalties for Making Tax Digital for Income Tax"
Dates can move. We checked each one on the date shown at the top of this page; check the source before you rely on a date for something that matters.
AEO Lookup editorial team
We write practical guides for people who run small UK firms, and we check every fact against its source on the date shown. Read how we review, or tell us if something has changed.