Every UK tax deadline, payment date and allowance reset in a single month-by-month reference. Covers personal tax (Self Assessment, Capital Gains Tax), business tax (VAT, PAYE, Corporation Tax), pension contributions, ISA allowances and key 2026/27 changes. Bookmark this page or print for the year ahead.
Last day to file SA online for 2025/26 and request coding-out (HMRC collects tax via PAYE next year).
31 December
Christmas-gift IHT 7-year rule continues - any substantial gifts to relatives logged.
January 2027
Date
Event
31 January
Self Assessment ONLINE deadline for 2025/26. Balancing payment + first POA for 2026/27 due. The single biggest UK tax date.
February 2027
Date
Event
1 February
£100 SA filing penalty applies if 2025/26 return not yet filed.
5 February
MTD ITSA Q3 update for 2026/27 (covering 6 Oct - 5 Jan).
28 February
End of "automatic interest period" for late 2025/26 SA payments.
March 2027
Date
Event
3 March
Spring Statement (timing varies year to year).
5 March
Final day to use 2026/27 ISA allowance, pension annual allowance, CGT AEA, dividend allowance, PSA, Gift Aid donations.
End of March
Pre-tax-year-end planning month. Final SIPP top-ups. Bed-and-ISA. CGT crystallisation. Marriage Allowance backdate windows close.
The 5 dates that catch UK filers out most
5 October 2026: Self Assessment registration deadline for first-time filers. £100 penalty for missing - many new self-employed people don’t know it exists separately from the filing deadline.
31 July 2026: Second Payment on Account. Often forgotten because it sits in summer holiday season.
5 April 2027: Last day to use 2026/27 allowances. ISA + pension + CGT AEA all reset on 6 April.
31 January 2027: Online SA deadline + balancing payment + first POA. The biggest single tax day - 11+ million UK Self Assessment filers.
April 2027: Pension benefits enter IHT for the first time (subject to consultation). Major estate planning change for higher-net-worth families.
How to cite this data
"UK Tax Drag 2026/27 Tax Calendar collates 47 key deadlines across personal tax, Self Assessment, VAT, PAYE, Corporation Tax, ISA and pension contributions for the UK 2026/27 tax year." - UK Tax Drag, May 2026
The questions readers most commonly ask about this topic. Each answer is reviewed by the UK Tax Drag editorial team against current HMRC, FCA and MoneyHelper guidance.
▸When does the 2026/27 UK tax year actually start?
The 2026/27 tax year starts on 6 April 2026 and ends on 5 April 2027. The unusual date is a legacy of the 1752 Gregorian calendar switch when 11 days were dropped. All allowances reset on 6 April: the £20,000 ISA, £3,000 CGT exemption, £500 dividend allowance, £1,000 personal savings allowance, £60,000 pension annual allowance, and the £3,000 IHT gifting allowance.
▸What are the key tax dates I should never miss?
Five non-negotiable dates: 5 April (tax-year end), 6 April (new-year reset), 5 October (Self Assessment registration deadline for first-timers), 31 January (online Self Assessment + balancing payment + first payment-on-account), 31 July (second payment-on-account). Each missed deadline triggers automatic penalties — even if you owe no tax.
▸When does HMRC issue new tax codes?
New tax codes for the upcoming year are typically issued in February-March, in time for the 6 April start. Check your code against the standard 1257L (£12,570 Personal Allowance) — if it differs, HMRC has applied an adjustment for benefits, taxable expenses, untaxed income, or previous-year underpayments. Errors are common: review the breakdown on the HMRC app or letter, and challenge anything you don't recognise.
▸When is the Budget announced and what changes?
The main Budget is delivered in autumn (typically November) and announces tax changes that take effect 6 April the following year. The Spring Statement (typically March) updates economic forecasts and can announce smaller measures. Some Budget items take effect immediately at midnight on Budget day — usually anti-forestalling measures and excise duty changes. Most income-tax changes apply from the next 6 April.
▸When do I need to make payments on account?
Payments on account are required if your previous Self Assessment tax bill was more than £1,000 AND less than 80% of your total tax was collected via PAYE. You pay half the previous year's tax bill on 31 January, the other half on 31 July, then balance up the following 31 January. You can reduce them if you think the current year's tax will be lower — but underpaying triggers interest.
▸When is the deadline to register a new business with HMRC?
Self-employed individuals must register for Self Assessment by 5 October following the tax year they started trading. So if you started self-employment any time during 2025/26 (between 6 April 2025 and 5 April 2026), you must register by 5 October 2026. Limited companies must register with Companies House first, then for Corporation Tax with HMRC within 3 months of starting to trade.
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