UK Tax Calendar 2025-26
Every key HMRC date for the 2025-26 tax year (6 April 2025 to 5 April 2026): Self Assessment deadlines, employer filing dates, PAYE RTI, VAT quarters, Corporation Tax, ISA cut-off, Payments on Account and the full HMRC penalty schedule for late filing.
On this page
2025-26 timeline, month by month
The entire UK tax year condensed into a visual timeline. Each month shows the statutory HMRC dates you cannot miss.
Self Assessment deadlines, the most important dates
Roughly 12 million people file Self Assessment in the UK. If you are self-employed, a company director, landlord, high earner (£100k+), receive untaxed income, or had the High Income Child Benefit Charge, these dates apply to you.
| Deadline | What's due | Applies to |
|---|---|---|
| 5 October 2025 | Register for Self Assessment | New sole traders, new landlords (2024-25) |
| 31 October 2025 | Paper SA return | 2024-25 paper filers only |
| 30 December 2025 | Online SA (PAYE coding) | If tax owed < £3,000 and want PAYE collection |
| 31 January 2026 | Online SA return + balancing payment + 1st POA | Everyone filing online for 2024-25 |
| 31 July 2026 | 2nd Payment on Account | 2024-25 payers with POA obligation |
Employer, PAYE & RTI deadlines
Employers running PAYE must submit Real Time Information (RTI) to HMRC on or before every payday, and pay PAYE/NIC monthly. Miss a deadline and HMRC applies graduated penalties for each late submission.
Monthly PAYE cycle
| Deadline | What to do |
|---|---|
| On or before payday | Submit Full Payment Submission (FPS) via RTI |
| 19th of following month | PAYE & NIC due (postal / cheque payment) |
| 22nd of following month | PAYE & NIC due (electronic payment) |
| 19th of following month | Employer Payment Summary (EPS) if required |
Annual employer deadlines
| Deadline | Document / action | Year covered |
|---|---|---|
| 19/22 April 2025 | Final FPS / EPS for 2024-25 | 2024-25 |
| 31 May 2025 | Issue P60 to all current employees | 2024-25 |
| 6 July 2025 | File P11D & P11D(b); give P11D copies to employees | 2024-25 |
| 19/22 July 2025 | Pay Class 1A NIC on benefits in kind | 2024-25 |
Note: from April 2026 HMRC is phasing in mandatory payrolling of benefits in kind, replacing the P11D form for most benefits. Employers should prepare systems accordingly.
Investment & allowance deadlines, use it or lose it
These allowances reset at the start of every tax year (6 April). Unused allowance does not carry over, if you don't use it by 5 April, it's gone forever.
| Allowance | 2025-26 limit | Deadline |
|---|---|---|
| ISA subscription (all types combined) | £20,000 | 5 April 2026 |
| Junior ISA / Child Trust Fund | £9,000 | 5 April 2026 |
| Lifetime ISA | £4,000 | 5 April 2026 |
| Pension Annual Allowance (gross) | £60,000 | 5 April 2026 |
| CGT annual exempt amount | £3,000 | 5 April 2026 |
| Dividend Allowance | £500 | 5 April 2026 |
| Personal Savings Allowance (Basic Rate) | £1,000 | 5 April 2026 |
| Gift Aid cash donations carry back | No limit | 31 Jan 2026 SA |
VAT & Corporation Tax
VAT, quarterly returns
VAT-registered businesses (turnover >£90,000 threshold from April 2024) file quarterly. The deadline is 1 month and 7 days after the end of each VAT quarter, both to submit the return and to pay. Example quarters:
| VAT quarter ending | Submission & payment deadline |
|---|---|
| 30 April 2025 | 7 June 2025 |
| 31 July 2025 | 7 September 2025 |
| 31 October 2025 | 7 December 2025 |
| 31 January 2026 | 7 March 2026 |
All VAT-registered businesses must use Making Tax Digital-compatible software. Late VAT returns trigger the new points-based penalty system introduced in January 2023.
Corporation Tax
Different from Self Assessment, Corporation Tax follows your company's accounting period, not the tax year:
- Pay Corporation Tax: 9 months and 1 day after the end of your accounting period. Example: year end 31 March 2025 → pay by 1 January 2026.
- File CT600 return: 12 months after the end of your accounting period. Note, you must PAY before you FILE.
- Large companies (profits >£1.5m): pay Corporation Tax in quarterly instalments.
- Main rate: 25% on profits above £250,000. Small profits rate: 19% on profits below £50,000. Marginal relief between.
Late filing penalties, HMRC's sliding scale
HMRC penalties for late Self Assessment are automatic, cumulative, and apply even if you owe £0 in tax. This is the full ladder:
Late filing penalties (Self Assessment)
| How late | Penalty | Cumulative |
|---|---|---|
| 1 day late | £100 fixed | £100 |
| 3 months late | £10/day for up to 90 days (£900 max) | Up to £1,000 |
| 6 months late | £300 or 5% of tax due (higher) | Up to £1,300+ |
| 12 months late | Another £300 or 5% (higher) | Up to £1,600+ |
Late payment penalties (on top of filing penalties)
| Payment late by | Penalty |
|---|---|
| 30 days | 5% of unpaid tax |
| 6 months | Additional 5% |
| 12 months | Additional 5% |
Can I appeal? Yes, HMRC accepts "reasonable excuse" appeals within 30 days of the penalty. Valid excuses include serious illness, bereavement, and genuine technical failures of the HMRC online system. "I forgot" or "I was too busy" are not accepted.
Why the UK tax year starts on 6 April
The UK's peculiar tax year dates back to 1752, when Britain switched from the Julian to the Gregorian calendar and had to "skip" 11 days. To avoid losing tax revenue, the Treasury extended the tax year that finished on 25 March (Lady Day, the traditional start of the English year) by 11 days, landing on 5 April. A further adjustment in 1800 pushed it by one more day to 6 April, where it has stayed ever since. Every other major economy aligns the tax year with the calendar year or the fiscal year (1 July in Australia, 1 April in Japan), the UK is virtually alone in using 6 April.
How to stay on top of HMRC deadlines
The single best habit you can develop is filing your Self Assessment in April or May, as soon as the new tax year opens. You have had all the necessary data (P60, P11D, interest certificates) for weeks, HMRC's system is empty, and you can pay a tiny balancing payment nine months later. Compare that to January, when 3 million people jostle for the HMRC phone lines and servers slow under peak load. Filing early does not mean paying early, you still have until 31 January of the following year to pay.
For employers, the PAYE cycle is unforgiving: you must submit a Full Payment Submission on or before every payday, and pay the resulting PAYE and NIC by the 22nd of the following month (electronic). Setting up a Direct Debit with HMRC removes the payment step entirely, HMRC pulls the exact amount on the due date.
Changes to watch in 2025-26 and beyond
Several big administrative changes are approaching:
- Making Tax Digital for Income Tax (MTD ITSA) begins in April 2026 for sole traders and landlords with gross income above £50,000, and in April 2027 for those above £30,000. Quarterly digital updates will be required on top of the annual Self Assessment.
- Mandatory payrolling of benefits in kind from April 2026, most employers will process benefits through payroll in real time instead of filing P11Ds after the year end.
- Basis period reform completed for 2024-25. Sole traders now all report on a tax-year basis (6 April to 5 April).
- Non-dom regime abolition from 6 April 2025, replaced by a residence-based 4-year FIG regime for new arrivals.
Tools to help you plan
Use our salary calculator to project your take-home pay for 2025-26, the Self Assessment guide for the full filing walk-through, and our pension calculator to check how much Annual Allowance you have left before 5 April 2026. If you are sitting on gains, the CGT calculator will show what you can crystallise inside the £3,000 annual exemption before it resets.
Frequently asked questions
When does the 2025-26 UK tax year start and end?
The 2025-26 tax year runs from 6 April 2025 to 5 April 2026. All income, pension contributions, ISA subscriptions and CGT disposals in this window fall into the 2025-26 tax year. The 6 April start date dates back to Britain's 1752 Gregorian calendar switch, a historical quirk that has never been changed.
What is the Self Assessment deadline for 2024-25?
The online SA deadline for 2024-25 is 31 January 2026 at 23:59. The paper deadline is 31 October 2025. You must also pay any tax owed plus your first 2025-26 Payment on Account by 31 January 2026. Miss the deadline and an automatic £100 penalty applies, even if you owe no tax. See our Self Assessment guide.
What is a Payment on Account and when is it due?
Payments on Account are advance payments towards next year's SA bill, required if your last tax bill was £1,000 or more and less than 80% was collected through PAYE. Each instalment is 50% of your previous year's tax liability. The first is due by 31 January (alongside the balancing payment), the second by 31 July.
What is the penalty for filing Self Assessment late?
HMRC charges £100 automatically the moment you miss 31 January, even with no tax due. After 3 months, £10/day applies (up to £900 extra). After 6 months, another £300 or 5% of tax (higher) is added. After 12 months, another £300 or 5%. On top: late-payment penalties of 5% at 30 days, 6 months, and 12 months. Interest accrues at Bank of England base + 4% from 1 February.
When is the ISA deadline for 2025-26?
The 2025-26 ISA allowance of £20,000 must be used by 5 April 2026. Unused ISA allowance does not roll over. Most providers have internal cut-offs before midnight on 5 April (some close at 3pm that day), so contribute a few days early. The same deadline applies to the £3,000 CGT exemption, £60,000 pension Annual Allowance and £500 Dividend Allowance.