Don’t miss the tax return deadline! Use our interactive deadline checker to find out exactly when your Self Assessment is due and how much time you have left. Includes penalty information and expert tips.
The Self Assessment tax return deadline is one of the most important dates in the UK tax calendar. Missing it can result in automatic penalties starting from £100, plus interest on unpaid tax.
Whether you're a self-employed professional, a property owner, or filing for the first time, use our interactive deadline checker to find out exactly when your return is due and how much time you have left.
Need help filing on time? Our ACCA-qualified accountants can handle your entire tax return.
Select your scenario below to see exactly when your tax return is due.
Mark these crucial dates in your calendar. Missing any of these deadlines can result in automatic penalties and interest charges from HMRC.
| Deadline | Date | What You Need to Do | Penalty for Missing |
|---|---|---|---|
| Register for Self Assessment | 5 October 2026 | Register if you're new to Self Assessment for the 2025-26 tax year | £100 penalty |
| Paper Tax Return | 31 October 2026 | Submit your paper tax return by this date | £100 penalty + daily penalties |
| Online Tax Return | 31 January 2027 | Submit your online tax return (the main deadline) | £100 penalty (increases over time) |
| Pay Tax Bill | 31 January 2027 | Pay your tax bill for the 2025-26 tax year | Interest + surcharges |
| Payments on Account | 31 July 2027 | Second payment on account for the 2026-27 tax year | Interest charges |
⚠️ Important: The 31 January 2027 deadline is for both filing your online return and paying your tax bill. You must do both by this date to avoid penalties.
HMRC imposes a strict penalty regime for late filing and late payment. Here's what you can expect:
If you're registering for Self Assessment for the first time for the 2025-26 tax year, you must register by 5 October 2026.
Who needs to register?
Unsure? Read our guide: Do I Need to File a Self Assessment?
⚠️ Important: If you miss the 5 October registration deadline, you may face a £100 penalty even if you don't owe any tax. Register as early as possible!
If your tax bill is more than £1,000 (or you pay at least 20% of your income through Self Assessment), HMRC will require you to make Payments on Account — advance payments towards the following year's tax bill.
Each payment is roughly 50% of the previous year's tax bill.
If your income is lower than the previous year, you can claim to reduce your Payments on Account. However, if you reduce them too much, HMRC may charge interest on the underpayment.
Filing on time doesn't have to be stressful. Follow these steps to stay ahead of the deadline:
Collect all your income and expense records, P60s, bank statements, and receipts. Our tax return document checklist shows you everything you need.
Make sure you have your UTR number and HMRC online account set up well in advance.
Don't wait until January. Start your return as soon as you have all your documents. This gives you time to check for errors.
Use our tax calculators to estimate your bill and double-check your figures.
Submit your return online and pay any tax due by 31 January. Pay early to avoid last-minute payment issues.
If you're unsure about anything, contact our accountants. We can file your return on your behalf and ensure you meet the deadline.
What is the deadline for online tax returns 2026?
The deadline for online Self Assessment tax returns for the 2025-26 tax year is 31 January 2027. This is also the deadline for paying your tax bill.
What happens if I miss the 31 January deadline?
You will face an automatic £100 penalty if your return is up to 3 months late. After that, additional penalties of £10 per day apply, plus percentage-based penalties on the tax due. Read the full penalty guide →
When is the deadline for paper tax returns?
Paper tax returns must be submitted by 31 October 2026 for the 2025-26 tax year. This is the earlier deadline — you cannot file a paper return after this date.
When do I need to register for Self Assessment?
You must register by 5 October 2026 for the 2025-26 tax year. If you miss this deadline, you may face a £100 penalty. How to register for Self Assessment →
What are Payments on Account and when are they due?
Payments on Account are advance payments towards your next tax bill. The first payment is due on 31 January and the second on 31 July. Each payment is roughly 50% of your previous year's tax bill.
Can I get an extension on the tax return deadline?
HMRC does not grant extensions for personal tax returns except in exceptional circumstances (e.g., serious illness or bereavement). You should always aim to file by the deadline.
What if I'm abroad and need to file a UK tax return?
The deadlines still apply if you are abroad. You can file online from anywhere in the world. If you need help, our expat tax specialists can assist you.
Here are our most popular calculators and guides to help you manage your tax deadlines:
Need help filing your Self Assessment on time?
Our ACCA-qualified accountants can handle everything — from registration to submission. We offer fixed fees with seasonal offers available.
How it works: Complete our online form → Make advance payment → We handle your return with HMRC
We're qualified UK accountants who specialise in Self Assessment tax returns.
Our mission is simple: provide professional, accurate tax return preparation
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