Important: FilingFriend provides general informational guidance about UK filing requirements. It does not provide tax, accounting, or legal advice. Always confirm requirements with HMRC or Companies House.
What the 2026 deadline usually means
HMRC's main online Self Assessment deadline is 31 January after the end of the tax year. That means 31 January 2026 is the online filing deadline for the tax year that ended on 5 April 2025.
This date is also normally the deadline to pay any balancing tax owed for that tax year and the first payment on account for the following year, if payments on account apply to you.
Paper and online returns do not share the same deadline
Paper tax returns are due earlier. HMRC says paper returns for a tax year must usually reach HMRC by 31 October after that tax year ends.
Most small business owners and landlords file online, but the earlier paper deadline matters if you are switching methods or dealing with an older process.
What to do if you want less deadline pressure
Keep your records up to date before the year end rather than waiting until January. The January deadline is fixed, but the stress around it usually comes from late bookkeeping, missing figures, or forgetting about payments on account.
If you are filing for the first time, check whether you also need to register with HMRC by 5 October after the tax year in which your untaxed income began.
Key deadlines
| Action | Deadline | Why it matters |
|---|---|---|
| Register for Self Assessment if you need to file | 5 October 2025 | Applies if the 2024 to 2025 tax year was your first year needing a return. |
| Paper tax return for the 2024 to 2025 tax year | 31 October 2025 | HMRC's earlier deadline for paper filing. |
| Online tax return, balancing payment, and first payment on account | 31 January 2026 | The date most people mean when they say the Self Assessment deadline 2026. |
| Second payment on account | 31 July 2026 | Only applies if you are required to make payments on account. |
Official references
FAQ
Does 31 January 2026 cover both filing and payment?
Usually yes. HMRC treats 31 January as the deadline for the online return and the balancing payment for the 2024 to 2025 tax year. It can also be the deadline for a first payment on account.
What if I miss 31 January 2026?
HMRC can charge late filing penalties and interest on late tax. If you think you will miss the deadline, check HMRC guidance immediately and act as quickly as possible.
Next step
Keep the main dates visible
Use the FilingFriend calendar as a quick reminder layer, then return to this guide when you need the fuller explanation or official source links.