The UK tax year does not follow the calendar year. It runs from 6 April to 5 April — a quirk that dates back to 1752, when the switch from the Julian to the Gregorian calendar shifted the start of the fiscal year. Knowing the exact dates matters: miss a Self Assessment deadline and you face an automatic £100 penalty even if you owe no tax.
This guide sets out every key date for the 2026/27 tax year and the deadlines that fall within it.
When the 2026/27 Tax Year Starts and Ends
| Event | Date |
|---|---|
| 2026/27 tax year begins | 6 April 2026 |
| 2026/27 tax year ends | 5 April 2027 |
| 2025/26 tax year ended | 5 April 2026 |
Income, gains, and allowances are measured against this 6 April – 5 April window. The Personal Allowance, ISA allowance, Capital Gains Tax annual exempt amount, and pension annual allowance all reset on 6 April 2026.
Self Assessment Deadlines for the 2025/26 Tax Year
The return you file during 2026/27 covers the 2025/26 tax year (the year that ended 5 April 2026). These are the deadlines that bite first:
| Deadline | Date | What it covers |
|---|---|---|
| Register for Self Assessment | 5 October 2026 | If you’re new to Self Assessment for 2025/26 |
| Paper tax return | 31 October 2026 | HMRC must receive your paper return by 11:59pm |
| Online tax return | 31 January 2027 | Submit your 2025/26 return online by 11:59pm |
| Pay tax owed (balancing payment) | 31 January 2027 | Settle your 2025/26 bill by 11:59pm |
| Tax coded out via PAYE | 30 December 2026 | File online by this date if you want HMRC to collect a small bill (under £3,000) through your tax code |
Miss the online filing deadline and you get an automatic £100 penalty, even if there’s no tax to pay. Further penalties build after 3, 6, and 12 months.
Payments on Account
If your Self Assessment bill is more than £1,000 (and less than 80% of your tax is collected at source), HMRC asks you to make payments on account — advance instalments towards the next year’s bill.
| Payment | Date | Amount |
|---|---|---|
| First payment on account | 31 January 2027 | 50% of your 2025/26 bill |
| Second payment on account | 31 July 2026 | 50% of your 2024/25 bill (towards 2025/26) |
The dates can feel counter-intuitive because two tax years overlap. On 31 January 2027 you may settle the 2025/26 balancing payment and make the first payment on account for 2026/27. On 31 July 2026 the second payment on account for 2025/26 falls due. If your income has dropped, you can apply to reduce your payments on account — see our payment on account calculator.
PAYE and Employer Deadlines
Employers operating PAYE have monthly deadlines that recur throughout 2026/27:
| Deadline | Date | What it covers |
|---|---|---|
| PAYE electronic payment | 22nd of the month | PAYE and NICs for the tax month ending on the 5th |
| PAYE cheque payment | 19th of the month | The cleared-funds deadline if you still pay by post |
| Final FPS for 2025/26 | 5 April 2026 / 19 April 2026 | Last Full Payment Submission of the year |
| P60 to employees | 31 May 2026 | For the 2025/26 tax year |
| P11D and P11D(b) | 6 July 2026 | Report 2025/26 benefits in kind |
| Class 1A NIC on benefits | 22 July 2026 | Electronic payment (19 July for cheque) |
A “tax month” runs from the 6th to the 5th, so the PAYE you owe for, say, 6 May – 5 June is due by 22 June electronically.
VAT Return Deadlines
For standard quarterly VAT returns, the rule is one calendar month plus 7 days after the end of your VAT accounting period. Both the return and the payment must reach HMRC by that date.
| VAT quarter ends | Return and payment due |
|---|---|
| 30 April 2026 | 7 June 2026 |
| 31 May 2026 | 7 July 2026 |
| 30 June 2026 | 7 August 2026 |
Almost all VAT-registered businesses must now keep digital records and file through Making Tax Digital-compatible software. See our guide on VAT return deadlines and payment dates for the late-submission penalty rules.
Corporation Tax Deadlines
For companies, the deadlines depend on your accounting period rather than the tax year:
| Deadline | Timing |
|---|---|
| Pay Corporation Tax | 9 months and 1 day after your accounting period ends |
| File Company Tax Return (CT600) | 12 months after your accounting period ends |
So a company with a 31 March 2026 year-end must pay by 1 January 2027 and file by 31 March 2027. Large companies (profits over £1.5 million) pay in quarterly instalments instead.
Other Dates Worth Diarising
- 5 April 2026 — last day to use your 2025/26 ISA allowance (£20,000) and CGT annual exempt amount (£3,000)
- 6 April 2026 — new allowances and any rate changes take effect
- 31 January 2027 — the single most important date for Self Assessment taxpayers
Key Takeaway
The 2026/27 tax year runs 6 April 2026 to 5 April 2027, but the deadlines that fall within it relate to the 2025/26 return: paper filing by 31 October 2026, online filing and payment by 31 January 2027, with the second payment on account due 31 July 2026. Diarise these dates early — the penalties for missing them are automatic.
Use the take-home pay calculator and income tax calculator to check your 2026/27 figures, and the payment on account calculator to plan your instalments.