Tax deadlines in the UK rarely feel urgent—until suddenly they are. One day, you’re confident you’ll “do it early this year,” and the next, it’s January, your inbox is full of HMRC reminders, and you’re unsure which tax year applies, what payments on account mean, or how quickly penalties stack up.
If that sounds familiar, you’re not alone. Every January, millions of UK taxpayers scramble to file their Self Assessment return before the 31 January deadline, often confused by overlapping dates, payment rules, and refund timelines.
This guide is written for real people, not accountants. It brings together every UK tax return date for 2024/25 and 2025/26 into one clear roadmap, explains what actually matters in January 2026, and provides simple systems to stay compliant without stress.
By the end, you’ll understand:
- All key UK tax return dates for 2024/25 and 2025/26
- Exactly what’s due on 31 January, 31 July, and 31 October
- Who must file a Self Assessment return
- How payments on account really work
- When to expect your refund
- Penalties for missing deadlines
A practical checklist and a memorable system to avoid mistakes
UK Tax Return Dates at a Glance (Fast Breakdown)
If you remember nothing else, remember this:
Most people must file and pay by 31 January 2026 for the 2024/25 tax year.
Here’s the simplified overview:
| Date | What It Means | Tax Year |
|---|---|---|
| 31 October 2025 | Paper tax return deadline | 2024/25 |
| 31 January 2026 | Online filing + balancing payment due | 2024/25 |
| 31 July 2026 | Second payment on account | 2025/26 |
Everything else revolves around these dates.
How UK Tax Years Work (Why Dates Matter)
The UK tax year doesn’t follow the calendar year, which is the root of most confusion.
Tax Year 2024/25 (Current Filing Year)
- Starts: 6 April 2024
- Ends: 5 April 2025
- Online filing deadline: 31 January 2026
This is the return most people are dealing with right now.
Tax Year 2025/26 (Upcoming Year)
- Starts: 6 April 2025
- Ends: 5 April 2026
- Online filing deadline: 31 January 2027
These dates matter for planning and payments on account.
All Key UK Tax Deadlines (Updated for January 2026)
2024/25 Critical Dates
| Date | What Happens | What You Should Do |
|---|---|---|
| 5 April 2025 | Tax year ends | Finalise income and expense records |
| 6 April 2025 | Filing opens | You can submit early |
| 31 October 2025 | Paper deadline | Must be posted by midnight |
| 30 December 2025 | PAYE coding option deadline | Tax collected via PAYE if eligible |
| 31 January 2026 | Online deadline + payment due | File and pay in full |
2025/26 Forward-Looking Dates
| Date | Event | Notes |
|---|---|---|
| 6 April 2025 | New tax year begins | Income starts counting |
| 31 July 2026 | Second payment on account | Applies if required |
| 5 April 2026 | Tax year ends | Keep records organised |
| 31 January 2027 | Online filing deadline | For 2025/26 return |
Who Must File a Self-Assessment Tax Return?
You must usually file if you:
- Are self-employed and have earned over £1,000
- Earn rental income as a landlord
- Earn over £100,000
- Have untaxed income (freelance work, side gigs, crypto, investments)
- Claim expenses over £2,500
- Receive dividends above the allowance
- Owe Capital Gains Tax
- Are a business partner
- Receive a notice to file from HMRC
You usually don’t need to file if:
- All income is taxed through PAYE
- You have no additional untaxed income
- HMRC hasn’t asked you to submit a return
If HMRC asks you to file, you must do so—even if your income is low.
Also Check: List of Tax Codes and What They Mean HMRC: Complete Guide 2026
The 5D Tax Date System (A Simple Way to Remember Everything)
This guide uses a simple framework to make deadlines stick.
D1 — Dates
Remember the three core dates: 31 January, 31 July, 31 October.
D2 — Duties
Confirm whether you actually need to file.
D3 — Deadlines
Paper and online deadlines are different—missing the right one triggers penalties.
D4 — Deductions
Track expenses early to reduce tax legally.
D5 — Dangers
Penalties and interest grow automatically when deadlines are missed.
Payments on Account (Explained Without Jargon)
Payments on account confuse more people than any other tax rule.
What They Are
If your tax bill is over £1,000, HMRC asks you to pay part of next year’s tax in advance.
How They Work
You make two advance payments:
- 31 January
- 31 July
Simple Example
If your 2024/25 tax bill is £2,000:
- £1,000 due on 31 January 2026
- £1,000 due on 31 July 2026
These payments are adjusted next year based on your actual income.
Penalties for Missing UK Tax Deadlines
Late Filing Penalties
- 1 day late: £100
- 3 months late: £10 per day (up to £900)
- 6 months late: £300 or 5% of tax owed
- 12 months late: another £300 or 5%
Late Payment Penalties
- 30 days late: 5%
- 6 months late: +5%
- 12 months late: +5%
Interest
Interest accrues daily until the balance is cleared.
When Will You Get Your Tax Refund?
| Filing Method | Typical Refund Time |
|---|---|
| Online | 3–14 days |
| Paper | 3–6 weeks |
| Amended return | Up to 12 weeks |
Refunds may be delayed if:
- PAYE data doesn’t match
- Additional checks are required
- Bank or address details recently changed
Also Check: Unclaimed Tax Refund HMRC: How to Check & Claim Money Owed (2026 Guide)
10-Minute Self Assessment Checklist
Before filing, gather:
- UTR number
- Government Gateway login
- National Insurance number
- Income records (employment, freelance, rental)
- Expense receipts
- Pension contributions
- Dividend statements
- Bank interest
- Gift Aid donations
- Crypto or capital gains records
Common Tax Return Mistakes (And How to Avoid Them)
The most frequent errors:
- Filing online but forgetting to pay
- Missing payments on account
- Reporting gross instead of net income
- Using incorrect expense categories
- Forgetting student loan repayments
- Missing PAYE coding deadlines
- Not updating personal details with HMRC
Most penalties come from simple oversight—not fraud.
What’s Changing in 2025/26 and Beyond
Looking ahead:
- Greater HMRC automation
- Faster digital refunds
- Tighter anti-fraud checks
- Expansion of Making Tax Digital for sole traders
- Increased reliance on digital receipts and records
From April 2026, MTD will become mandatory for many higher-earning self-employed individuals and landlords.
FAQs
Q. What are the UK tax return dates for the 2024/25 tax year?
For the 2024/25 tax year, the paper Self Assessment deadline is 31 October 2025, and the online filing deadline is 31 January 2026. Most taxpayers file online and must submit and pay by 31 January 2026.
Q. When does the UK tax year start and end?
The UK tax year always starts on 6 April and ends on 5 April the following year. This applies to all individuals, self-employed workers, and landlords.
Q. When will I receive my UK tax refund?
If you file your Self Assessment online, refunds usually arrive within 3 to 14 days.
If you file a paper return, refunds typically take 3 to 6 weeks, depending on HMRC checks.
Q. What happens if I miss the 31 January tax return deadline?
If you miss the 31 January deadline, HMRC issues an automatic £100 late filing penalty, even if no tax is owed. Additional daily penalties and interest apply if the delay continues beyond three months.
Q. When is the second payment on account due?
The second payment on account is due on 31 July 2026. This applies to taxpayers whose previous tax bill exceeded £1,000 and is part of HMRC’s advance payment system.
Q. Is 31 January the same date for filing and paying tax?
Yes. For most taxpayers, 31 January is both the online filing deadline and the final date to pay any tax owed for the previous tax year.
Q. Can I file my UK tax return early?
Yes. Online filing opens on 6 April after the tax year ends, and submitting early can speed up refunds and reduce last-minute stress.
Q. Do these deadlines apply to self-employed and landlords?
Yes. The same Self Assessment deadlines apply to self-employed individuals, landlords, and anyone required to file a UK tax return.
Final Thoughts: How to Make January 2026 Stress-Free
For January 2026, the most important date is clear:
31 January 2026 — online filing and payment deadline for the 2024/25 tax year.
Understanding tax year boundaries, planning for payments on account, and keeping records organised removes nearly all the stress. File early if you can, use the checklist, and treat tax deadlines as fixed milestones—not last-minute surprises.
With the right system, tax season becomes manageable instead of overwhelming.
Related: Business Tax Return 2026: UK & US Deadlines, Forms & Filing
