The UK tax year — officially called the fiscal year — runs from 6 April to 5 April the following year. This quirky start date dates back to the switch from the Julian to the Gregorian calendar in 1752, when 11 days were lost from the calendar. The Treasury refused to lose 11 days of tax revenue, so the tax year shifted accordingly.
The 2025-26 tax year runs from 6 April 2025 to 5 April 2026. For self-assessment purposes, tax returns for 2024-25 are due by 31 January 2026, which falls within the 2025-26 tax year.
Key 2025-26 Tax Facts
Personal Allowance: £12,570 | Basic Rate (20%): £12,571–£50,270 | Higher Rate (40%): £50,271–£125,140 | Additional Rate (45%): over £125,140 | National Insurance: 8% (£12,570–£50,270), 2% above
Master Deadline Table: All UK Tax Deadlines 2025-26
The table below covers every major HMRC deadline across self-assessment, PAYE, VAT, and corporation tax for the 2025-26 tax year period.
| Date | Deadline | Who It Affects | Penalty if Missed |
|---|---|---|---|
| 5 Apr 2025 | End of 2024-25 tax year | Everyone | — |
| 6 Apr 2025 | Start of 2025-26 tax year | Everyone | — |
| 5 Oct 2025 | Register for self-assessment (2024-25) | New self-assessment taxpayers | Penalty based on unpaid tax |
| 19 Oct 2025 | PAYE/NI payment (cheque) – Q2 | Employers paying quarterly | Interest + surcharges |
| 31 Oct 2025 | Paper self-assessment return (2024-25) | Self-employed, landlords, directors | £100 immediate |
| 19 Jan 2026 | PAYE/NI payment (cheque) – Q3 | Employers paying quarterly | Interest + surcharges |
| 31 Jan 2026 | Online self-assessment return (2024-25) | Self-employed, landlords, directors | £100 immediate |
| 31 Jan 2026 | Tax payment (2024-25 balancing) | Self-assessment taxpayers | 5% surcharge + interest |
| 31 Jan 2026 | 1st Payment on Account (2025-26) | Self-assessment taxpayers | 5% surcharge + interest |
| 5 Apr 2026 | End of 2025-26 tax year | Everyone | — |
| 6 Apr 2026 | Start of 2026-27 tax year | Everyone | — |
| 31 Jul 2026 | 2nd Payment on Account (2025-26) | Self-assessment taxpayers | 5% surcharge + interest |
| 31 Jan 2027 | Online self-assessment return (2025-26) | Self-assessment taxpayers | £100 immediate |
Deadline Reminder Calculator
Find out how many days remain until your next key tax deadline.
Days Until Your Deadline
New Tax Year Begins
2025-26 tax year starts. New allowances and thresholds apply from this date. P60s issued to employees by 31 May.
P60 Issued to Employees
Employers must give P60s to all employees who were on their payroll on 5 April 2025.
P11D Submission Deadline
Employers must submit P11D forms reporting employee benefits in kind for 2024-25.
2nd Payment on Account (2024-25)
Second instalment of estimated tax bill for 2024-25. Each payment is 50% of the prior year's tax liability.
Register for Self-Assessment
Deadline to tell HMRC you need to complete a tax return for 2024-25.
Paper Tax Return Deadline
Last date to file a paper self-assessment return for 2024-25 tax year.
THE KEY DEADLINE — Three Things Due
1. Online self-assessment return for 2024-25. 2. Balancing payment of tax owed for 2024-25. 3. First payment on account for 2025-26. HMRC receives millions of returns on this single day — file early to avoid website delays.
2nd Payment on Account (2025-26)
Second of two advance payments toward your 2025-26 tax bill. Each is 50% of your 2024-25 tax liability.
Payments on account are advance payments toward your next year's tax bill. If your self-assessment tax bill for the previous year exceeded £1,000 and less than 80% was deducted at source (e.g. via PAYE), HMRC requires you to make two payments on account.
How Payments on Account Work
- Each payment = 50% of your previous year's total income tax and Class 4 NI liability
- First payment: Due 31 January (same as your return deadline)
- Second payment: Due 31 July
- Balancing payment: Due 31 January the following year — the difference between what you paid on account and what you actually owed
Example: Payment on Account Calculation
If your 2024-25 tax bill was £6,000 and less than 80% was deducted via PAYE:
- By 31 Jan 2026: Pay £6,000 (2024-25 balancing payment) + £3,000 (1st payment on account for 2025-26)
- By 31 Jul 2026: Pay £3,000 (2nd payment on account for 2025-26)
- By 31 Jan 2027: Pay any remaining 2025-26 tax minus the £6,000 already paid on account
Can You Reduce Payments on Account?
Yes. If you expect your 2025-26 income to be lower than 2024-25, you can apply to reduce your payments on account using form SA303 via your HMRC online account. However, if you reduce them too much, HMRC will charge interest on the shortfall.
What Happens if You Miss the 31 January Deadline?
Missing the 31 January self-assessment deadline triggers an immediate £100 fixed penalty — even if you have no tax to pay or have already paid all the tax you owe. The penalties escalate significantly:
- Day 1 after deadline: £100 automatic penalty
- After 3 months (30 April): £10 per day, up to 90 days maximum (£900 additional)
- After 6 months (31 July): Greater of £300 or 5% of the tax due
- After 12 months (31 January 2027): A further £300 or 5% of the tax due (whichever is higher)
- Interest: Charged on unpaid tax at Bank of England base rate + 2.5%
VAT Return Deadlines
VAT-registered businesses must file VAT returns and pay VAT due by the VAT payment deadline — typically one month and seven days after the end of each VAT accounting period. Most businesses file quarterly, though monthly and annual VAT accounting is also available.
Corporation Tax Deadlines
Corporation tax returns (CT600) must be filed within 12 months of your company's accounting period end. Payment is due nine months and one day after your accounting period ends (for companies with profits under £1.5m). Large companies pay in quarterly instalments.