Answers · UK 2025/26
When does the UK tax year start and end?
The UK tax year runs from 6 April to 5 April the following year. The 2026/27 tax year runs from 6 April 2026 to 5 April 2027. The unusual date stems from the 1752 calendar reform — the Treasury refused to lose 11 days of revenue when Britain adopted the Gregorian calendar.
Full answer
The UK tax year (also called the fiscal year or financial year for tax purposes) begins on **6 April** and ends on **5 April** the following year. This differs from the standard calendar year and from the government financial year (which runs April to March). **Why 6 April?** Britain switched from the Julian calendar to the Gregorian calendar in September 1752, losing 11 days overnight. The Treasury, unwilling to lose 11 days of tax revenue, moved the tax year end from 25 March (Lady Day — a traditional quarter day) forward by 11 days to 5 April. When the century-year adjustment was made in 1800, it shifted to 6 April, where it has remained ever since. **Current and recent tax years:** | Tax year | Runs from | Runs to | |---|---|---| | 2024/25 | 6 April 2024 | 5 April 2025 | | 2025/26 | 6 April 2025 | 5 April 2026 | | **2026/27** | **6 April 2026** | **5 April 2027** | | 2027/28 | 6 April 2027 | 5 April 2028 | **Key dates within the 2026/27 tax year:** - **6 April 2026** — New tax year begins; ISA allowances reset; new income tax and NI rates take effect - **5 October 2026** — Deadline to register for Self Assessment for 2025/26 - **31 October 2026** — Paper SA return filing deadline (for 2025/26) - **31 January 2027** — Online SA return deadline and payment of tax owed (for 2025/26) - **31 July 2027** — Second payment on account (for 2026/27) - **5 April 2027** — Tax year ends; final day to use ISA allowances and pension annual allowance **Government financial year:** HMRC and HMRC reporting use the 6 April–5 April cycle. However, government departmental spending (Spending Reviews, budgets) runs April to March — a different but similarly annual cycle. **Scotland:** The Scottish tax year follows the same 6 April–5 April cycle, even though Scottish Parliament uses calendar-year budgeting internally.
Try the calculator
This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.