Tax year dates
| Tax year | Starts | Ends |
|---|---|---|
| 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 |
When people say “the 2025/26 tax year” (or “2025-26”), they mean the year that started on 6 April 2025 and ended on 5 April 2026.
Why does the tax year start on 6 April?
It's a historical quirk. The year once started on 25 March (Lady Day). When Britain switched calendars in 1752, eleven days were dropped, and the tax year moved to 5 April so no tax was lost. A further adjustment in 1800 moved the start to 6 April, where it has stayed.
Useful tool
Countdown, penalties and every Self Assessment date in one place.
Self Assessment deadlines for each tax year
| Deadline | 2025/26 tax year | 2026/27 tax year |
|---|---|---|
| Register for Self Assessment | 5 October 2026 | 5 October 2027 |
| Paper return | 31 October 2026 | 31 October 2027 |
| Online return (to have tax collected via PAYE, if under £3,000) | 30 December 2026 | 30 December 2027 |
| Online return | 31 January 2027 | 31 January 2028 |
| Pay balancing payment + 1st payment on account | 31 January 2027 | 31 January 2028 |
| 2nd payment on account | 31 July 2027 | 31 July 2028 |
Missing these dates costs money — see Self Assessment penalties. Payments on account are explained in this guide.
Other dates to know
- 31 May: your employer must give you your P60 for the tax year just ended.
- 6 July: employers must report benefits in kind (P11D), so you should receive your P11D by then if you get benefits.
- Quarterly Making Tax Digital updates (if you're in scope from April 2026): see MTD for Income Tax.
You can file as soon as the tax year ends
You don't need to wait until January. From 6 April you can prepare your return for the year just ended. Filing early means you know your bill months in advance — and you still don't pay until 31 January. Start your return whenever your documents arrive.
Which tax year does my income belong to?
Income generally belongs to the tax year in which you receive it (self-employed profits follow the tax year too, under the current rules). Some examples:
| Income | Received on | Tax year |
|---|---|---|
| Salary for March | 31 March 2026 | 2025/26 |
| Salary for April | 30 April 2026 | 2026/27 |
| Dividend | 4 April 2026 | 2025/26 |
| Dividend | 7 April 2026 | 2026/27 |
| Bank interest credited | 5 April 2026 | 2025/26 |
Your P60 shows your pay and tax for a single tax year, so it's the easiest way to check employment income. For savings, use the interest statement covering 6 April to 5 April — or add up the interest credited in that window.
Self-employed? Most sole traders now report profits for the tax year itself. See the SA103 guide.