Live countdown to the end of the 2026/27 UK tax year. The current tax year ends on 5 April 2027. The new tax year begins on 6 April 2027.
Key UK tax year dates
| Date | Event |
|---|---|
| 6 April 2026 | 2026/27 tax year begins |
| 31 July 2026 | Second payment on account deadline (self assessment) |
| 5 October 2026 | Deadline to register for self assessment (new taxpayers) |
| 31 October 2026 | Paper tax return deadline for 2025/26 |
| 31 January 2027 | Online self assessment deadline for 2025/26 and first payment on account |
| 5 April 2027 | 2026/27 tax year ends |
| 6 April 2027 | 2027/28 tax year begins |
Why does the UK tax year end on 5 April?
The UK tax year ending on 5 April is a historical quirk dating back to 1752 when Britain switched from the Julian calendar to the Gregorian calendar. The old tax year ended on 25 March — Lady Day — which was the start of the new year under the old calendar. When 11 days were lost in the calendar change, the tax year end shifted to 5 April to avoid losing tax revenue. It has remained on that date ever since.
When does the UK tax year end?
The UK tax year always ends on 5 April, with the new tax year starting 6 April. For the 2026/27 tax year, that means it ends Monday 5 April 2027.
Common questions
Why does the UK tax year end on such an unusual date?
The unusual UK tax-year dates have historical roots. The tax year was once linked to Lady Day on 25 March. When Britain adopted the Gregorian calendar in 1752, the date moved by 11 days. A further one-day adjustment was made in 1800 because of the different leap-year rules used by the Julian and Gregorian calendars. That produced the modern tax year running from 6 April to 5 April.
What happens if I miss the 5 April deadline for things like ISA allowances?
Unused annual allowances (like your ISA allowance) don’t carry over — they reset on 6 April, so anything unused is lost.
Is the tax year end date the same for Self Assessment deadlines?
No — Self Assessment has separate deadlines (31 January for online filing and payment) that fall within the following tax year, not on the tax year end itself.
See also
Check our next UK bank holiday countdown, use our UK working days calculator to plan deadlines, or see our how many working days in 2026 guide.