Home › Trades and building firms
Key dates
Key dates for trades and building firms: October 2026 to July 2027
Dates for sole traders and small firms in the building trades: tax return and payment deadlines, the monthly CIS return, Making Tax Digital updates, the wiring regulations changeover, and the two days a year that set the interest rate on late business invoices. Dates that depend on your own year end or VAT quarter are left out.
Add all 13 dates to your calendar An .ics file for Outlook, Google Calendar or Apple Calendar. No sign-up.
October 2026
Comes round every year
Deadline to tell HMRC you need to send a 2025 to 2026 tax return
If you have not sent a Self Assessment return before, register by today. Register later and HMRC sets a return deadline 3 months from its letter, but the tax is still due by 31 January 2027. Who: Anyone newly self-employed in 2025 to 2026
Source: GOV.UK, Self Assessment tax returns: deadlines, read 1 October 2026
Previous edition of BS 7671 withdrawn; Amendment 4 forms only from today
Amendment 4 was published on 15 April 2026 and either edition could be used for six months. New certificates now use the Amendment 4 model forms. Work designed before today can still be certified to the previous version. Who: Electricians
Source: NICEIC, Understanding BS 7671:2018+A4:2026
Comes round every month
CIS monthly return due for the tax month ended 5 October
Contractors send a return by the 19th of every month, or a nil return if no subcontractor was paid. One day late costs £100, two months late £200, and at six months £300 or 5% of the deductions if that is higher. Who: CIS contractors
Full guide: CIS monthly return: the 19th deadline and what a late one costs
Source: GOV.UK, File your monthly CIS returns
Comes round every year
Paper Self Assessment return for 2025 to 2026 must reach HMRC
HMRC must receive a paper return by 11:59pm today or a late filing penalty applies, starting at £100. Online filers have until 31 January 2027.
Source: GOV.UK, Self Assessment tax returns: deadlines, read 1 October 2026
November 2026
Comes round every quarter
Making Tax Digital quarterly update due for 6 April to 5 October
Sole traders with qualifying income over £50,000 send a cumulative update through their software by the 7th of August, November, February and May. HMRC gives no penalty points for late updates in 2026 to 2027, but all four must be sent before the return. Who: Sole traders in Making Tax Digital for Income Tax
Full guide: Making Tax Digital for sole-trader trades: are you in, and what is due on 7 November
Source: GOV.UK, Send quarterly updates
December 2026
Last day to file online if the bill is to be collected through your tax code
GOV.UK says an online return must be submitted by 11:59pm on 30 December 2026 if you want to pay the bill through your tax code. Miss it and you pay another way by 31 January 2027.
Source: GOV.UK, Self Assessment tax returns: deadlines, read 1 October 2026
Comes round every year
Bank Rate today sets statutory interest on invoices that go late in January to June
Statutory interest on a late business invoice is 8% plus the Bank Rate in force on 31 December, for interest that starts between 1 January and 30 June. Check the rate before you put a daily figure in a final letter. Who: Firms with business customers
Free tool: Late payment interest calculator for UK trades: what a late business customer owes you
Source: Late Payment of Commercial Debts (Rate of Interest) (No. 3) Order 2002, article 4
January 2027
Comes round every year
Online tax return, balance for 2025 to 2026 and first payment on account due
File online and pay by 11:59pm. A late return costs £100 at once, and unpaid tax draws interest and a 5% penalty at 30 days. CIS deductions come off the bill, and no payments on account are due if less than £1,000 is left to pay. Who: Sole traders and partners
Source: GOV.UK, Self Assessment tax returns: deadlines and penalties, read 1 October 2026
April 2027
Last day of the £123.25 a week statutory sick pay rate for 2026 to 2027
The rate of £123.25 a week, or 80% of average weekly earnings if that is lower, runs from 6 April 2026 to 5 April 2027. Check GOV.UK for the next rate before you pay an absence that runs into the new tax year. Who: Employers
Full guide: Statutory sick pay from day one: what it costs a small trades firm since 6 April 2026
Source: GOV.UK, Statutory Sick Pay (SSP): employer guide
Tax year ends: 2026 to 2027 turnover sets the April 2028 Making Tax Digital test
From 6 April 2028 the Making Tax Digital line drops to £20,000, based on qualifying income for the 2026 to 2027 tax year, which ends today. Qualifying income is turnover before expenses, not profit. Who: Sole traders
Full guide: Making Tax Digital for sole-trader trades: are you in, and what is due on 7 November
Source: GOV.UK, Check if you're eligible for Making Tax Digital for Income Tax
Making Tax Digital line drops to £30,000 of qualifying income
Sole traders whose turnover before expenses was over £30,000 in 2025 to 2026 must keep digital records and send quarterly updates from today. Late updates earn penalty points from the 2027 to 2028 tax year, and four points means a £200 penalty. Who: Sole traders with turnover over £30,000
Full guide: Making Tax Digital for sole-trader trades: are you in, and what is due on 7 November
Source: GOV.UK, Check if you're eligible for Making Tax Digital for Income Tax
June 2027
Comes round every year
Bank Rate today sets statutory interest on invoices that go late in July to December
For interest that starts between 1 July and 31 December, statutory interest on a late business invoice is 8% plus the Bank Rate in force on 30 June. A calculator that asks for the current base rate can give the wrong figure. Who: Firms with business customers
Free tool: Late payment interest calculator for UK trades: what a late business customer owes you
Source: Late Payment of Commercial Debts (Rate of Interest) (No. 3) Order 2002, article 4
July 2027
Comes round every year
Second payment on account for 2026 to 2027 due
The second of two advance payments, each half of last year's bill including Class 4 National Insurance. It is not due if last year's balance was under £1,000, or if more than 80% of the tax was paid outside Self Assessment, which CIS deductions count towards. Who: Sole traders and partners
Source: GOV.UK, Understand your Self Assessment tax bill: payments on account, read 1 October 2026
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.