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UK Tax Year Dates for 2026/27
When the tax year starts and ends, every deadline between, and what resets on 6 April
UK Tax Year Dates · 2026/27
The dates that cost money if you miss them
Live countdowns to the deadlines that matter, then every date for the 2026/27 tax year in one table.
Every 2026/27 date in one place
| Date | What happens |
|---|---|
| 6 April 2026 | 2026/27 tax year begins. ISA and pension allowances reset. Dividend tax rates rise to 10.75% and 35.75%. Business Asset Disposal Relief reaches 18%. The Business Relief cap starts. |
| 31 July 2026 | Second payment on account for 2025/26 Self Assessment. |
| 5 October 2026 | Deadline to register for Self Assessment if you had new untaxed income in 2025/26. |
| 31 October 2026 | Paper Self Assessment return deadline for 2025/26. |
| 31 January 2027 | Online Self Assessment deadline for 2025/26, plus the balancing payment and first payment on account for 2026/27. |
| 5 April 2027 | 2026/27 tax year ends. Last day for this year’s ISA allowance, pension contributions against this year’s annual allowance, and the £3,000 gift exemption. |
| 6 April 2027 | 2027/28 begins. Unused pension funds join estates for inheritance tax under the Finance Act 2026. |
| 31 July 2027 | Second payment on account for 2026/27 Self Assessment. |
| 5 October 2027 | Deadline to register for Self Assessment if you had new untaxed income in 2026/27. |
| 31 October 2027 | Paper Self Assessment return deadline for 2026/27. |
| 31 January 2028 | Online Self Assessment deadline for 2026/27, plus the balancing payment and first payment on account for 2027/28. |
| 5 April 2028 | 2027/28 tax year ends. Last day for that year’s ISA allowance, pension contributions against its annual allowance, and the £3,000 gift exemption. |
Deadlines verified against gov.uk in August 2026 and refreshed every April and after each Budget. Payments on account apply where your last Self Assessment bill was over £1,000 and less than 80% was collected at source. Allowances that reset on 6 April are lost if unused: there is no carry forward for ISAs, and pension carry forward has its own rules. Talk to us before the year-end deadlines. The first conversation is free.
The tax year runs 6 April to 5 April. The deadlines do not wait.
The UK tax year runs from 6 April to 5 April. The 2026/27 tax year began on 6 April 2026 and ends on 5 April 2027. Everything annual keys off those dates. ISA allowances, pension allowances, capital gains exemptions and the gift exemption all reset on 6 April, and are lost if unused.
The deadlines in between are where the money is. Miss the 31 January Self Assessment deadline and penalties start at £100 and grow. Miss 5 April and this year’s £20,000 ISA allowance is gone for good. Leave pension funding to the final week and there is no room to fix a mistake with the tapered annual allowance or carry forward.
Year-end is also when planning compounds. Using both spouses’ allowances, timing gains against the £3,000 capital gains exemption, and topping up pensions against this year’s bands are all use-it-or-lose-it decisions. Our guide to saving tax with pensions covers the biggest of them.
Frazer James is an independent, FCA-regulated firm of Certified Financial Planners. This page is refreshed every April and after each Budget.
6 April: everything resets
ISA allowance, pension annual allowance, capital gains exemption and the £3,000 gift exemption all restart. None of them carry forward automatically, and unused ISA allowance is simply lost.
31 January: the expensive one
Online Self Assessment, the balancing payment and the first payment on account all land together. Penalties start at £100 the moment it is missed, even with no tax to pay.
5 April: the last word
The final day for this year’s allowances. Contributions and transfers need clearing before it, not starting on it. The practical deadline is days earlier than the calendar one.
Since working together, I feel more organised, more secure and more positive about the future. The advice has been exceptionally valuable, financially, professionally and personally.
Questions people ask about the tax year
When does the UK tax year start and end?
It runs from 6 April to 5 April the following year. The 2026/27 tax year started on 6 April 2026 and ends on 5 April 2027. The dates are a historical quirk from the calendar change of 1752, and every UK allowance and deadline keys off them.
When is the Self Assessment deadline?
For the 2025/26 tax year, register by 5 October 2026 if you are new to Self Assessment. Paper returns are due by 31 October 2026, and online returns by 11:59pm on 31 January 2027. The 31 January deadline also carries the balancing payment and, for many people, the first payment on account for 2026/27.
What are payments on account?
Advance payments towards next year’s tax bill, due 31 January and 31 July. They apply where your last Self Assessment bill was over £1,000 and less than 80% of your tax was collected at source. Each payment is half your previous year’s bill, and you can apply to reduce them if your income has fallen.
What happens if I miss the ISA deadline?
The allowance is lost. ISA allowances never carry forward: if you use £8,000 of this year’s £20,000 by 5 April 2027, the other £12,000 is gone for good. A new £20,000 allowance starts on 6 April, but it belongs to the new year.
Why does 6 April 2027 matter more than usual?
Because the Finance Act 2026 takes effect for deaths from that date: most unused pension funds join the estate for inheritance tax. Anyone with a large pension has this tax year to review beneficiaries, spending order and gifting plans under the current rules.
Reviewed by
BSc, MLIBF, PETR, Chartered ALIBF · Co-Founder and Chartered Associate
Chris has spent over a decade in financial planning and specialises in research and technical analysis. He checks every figure and calculation on this page before it is published.
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