Scope: These dates are for most individuals filing a UK Self Assessment return for the tax year from 6 April 2025 to 5 April 2026. Trustees, some non-resident companies and certain partnerships can have different rules.
The short answer
For the tax year ended 5 April 2026, the main dates are 5 October 2026 to notify HMRC where required, 31 October 2026 for most paper returns, 30 December 2026 if asking HMRC to collect eligible tax through a PAYE code, and 31 January 2027 for online filing and the main tax payment. A second payment-on-account date can fall on 31 July 2027.
HMRC must receive the return and cleared payment by the relevant deadline. Starting a payment on the final day does not necessarily mean HMRC receives it on time.
Main dates for the 2025 to 2026 return
| Date | What it is for | Who needs to act |
|---|---|---|
| 5 October 2026 | Tell HMRC that a return is needed | A new filer, or someone registered before who did not need a return for 2024 to 2025, where a 2025 to 2026 return is required. |
| 31 October 2026, 11:59pm | Paper tax return | Most people choosing to file on paper. |
| 30 December 2026, 11:59pm | Online filing when asking for eligible tax to be collected through the PAYE code | Filing by this date does not guarantee coding is available; HMRC’s eligibility conditions still apply. |
| 31 January 2027, 11:59pm | Online tax return and main payment | Most online filers; balancing tax and any first payment on account are generally dealt with at this point. |
| 31 July 2027 | Second payment on account | Only people required to make payments on account. |
Registering by 5 October 2026
Tell HMRC by 5 October if you need a return for 2025 to 2026 and have either never sent one, or registered before but did not need one for 2024 to 2025. HMRC’s route is the Self Assessment registration service.
If registration happens after 5 October, HMRC says it will send a letter or email with a return deadline three months from the date of that message. The tax payment can still be due by 11:59pm on 31 January 2027. Registering late therefore does not provide a general payment extension.
Paper return deadline: 31 October 2026
HMRC must receive a standard paper return by 11:59pm on 31 October 2026. Posting it on that date is not enough if it arrives later.
Someone who misses the paper deadline can usually consider filing online by 31 January instead, but should check that the return type is supported online and avoid filing both formats for the same obligation.
PAYE tax-code collection date: 30 December 2026
An eligible person who wants HMRC to consider collecting a Self Assessment amount through their PAYE tax code must file online by 11:59pm on 30 December 2026. Missing that date means another payment method will be needed.
This is an earlier filing date, not a different payment calculation. Coding is subject to HMRC’s conditions and should not be assumed merely because the return was filed by 30 December.
Online filing and payment: 31 January 2027
The online return must reach HMRC by 11:59pm on 31 January 2027. Tax due under the main Self Assessment deadline must also be received by then.
Filing and paying are separate actions. A successfully submitted return does not itself transfer the money, and making a payment does not submit the return.
Worked timeline
Priya needs to file online for 2025 to 2026 and expects to pay by bank transfer. She registers before 5 October, completes the return in November and checks the payment method’s processing time. She submits before 30 December only if she wants HMRC to consider PAYE-code collection; otherwise the ordinary online filing date remains 31 January 2027. Any payment due must reach HMRC by its deadline.
The timeline illustrates the sequence. It does not decide whether coding is available or whether payments on account apply.
Payments on account and 31 July
If payments on account apply, the first is normally associated with the 31 January bill and the second date is 31 July.
Payments on account are not an extra tax rate. They are advance payments towards the following year’s liability and depend on the Self Assessment calculation. Check the statement and calculation rather than assuming every filer pays them.
Cases with different filing rules
HMRC identifies exceptions including:
- trustees of a registered pension scheme and non-resident companies, which may have a 31 January paper deadline and cannot use the ordinary online return route; and
- a partnership with a limited company partner and an accounting date between 1 February and 5 April, where filing is measured from the accounting date.
These exceptions are not covered by the standard table alone. Use HMRC’s detailed deadline page for the exact entity and return.
If a deadline has been missed
Submit the outstanding return or payment as soon as possible. Waiting can expose the filer to further penalties or interest. Check the correspondence and HMRC account for the exact obligation and do not send duplicate returns.
Where payment cannot be made in full, contact HMRC about available payment support rather than delaying the return. Filing on time and paying on time are assessed separately.
What to do next
- Check whether a return is required.
- Register for Self Assessment if the notification rule applies.
- Choose paper or online filing and calendar the correct date.
- File early enough to correct validation or access problems.
- Check the payment method’s processing time and reference.
- Use the tax calculator library to find an estimate relevant to a specific income source; no current UK Tax Hero calculator represents a complete Self Assessment return.