Self Assessment Deadlines | Paisley & Glasgow | Marsal Accountants
Self Assessment Deadlines for Paisley, Glasgow & Central Scotland
HMRC must receive a paper Self Assessment return for 2025/26 by 11:59pm on 31 October 2026. If you file online, the deadline is 11:59pm on 31 January 2027. Tax you owe is also due by that January date.
Marsal Accountants is based in Paisley and helps sole traders, landlords, and company directors across Glasgow and Central Scotland get the return in on time.
Which deadline applies to you?
The tax year ran from 6 April 2025 to 5 April 2026.
| What you are doing | Deadline |
|---|---|
| Paper return received by HMRC | 31 October 2026 |
| Online return | 31 January 2027 |
| Pay the tax you owe | 31 January 2027 |
| Online return, if you want tax collected through your PAYE code (where you qualify) | 30 December 2026 |
Official dates are on GOV.UK: Self Assessment deadlines.
If 31 October passes and you have not sent a paper return, file online by 31 January. Do not post a paper return after 31 October and then file online as well. HMRC uses the first return it receives, so a late paper return can still trigger a penalty.
If you still need to register
The usual date to tell HMRC you need a return — because you have not sent one before, or you did not need one for 2024/25 — was 5 October 2026.
If that applies and you have not registered, do it now via Check how to register for Self Assessment. Telling HMRC after 5 October can mean a penalty. HMRC may then give you three months from the date on their letter to file, but the tax is still due by 31 January 2027.
Paying through your tax code
If you owe less than £3,000, HMRC may collect it through your wages or pension from April 2027, when your PAYE income can cover it. For an online return, that means filing by 30 December 2026. A paper return needs to arrive by 31 October 2026. Class 2 National Insurance is not collected this way.
If you miss 30 December, you pay another way — usually by 31 January. Check the current conditions on GOV.UK before you rely on coding out.
What to have ready in Paisley and Glasgow
- Income from self-employment, employment, dividends, and property
- Allowable expenses you can support with records
- CIS statements, if you work in construction
- Bank interest and any other untaxed income
- Payments you have already made on account
Scottish income tax bands apply to many people in Paisley and Glasgow when their tax code starts with S. The filing dates above are the same across the UK. The tax calculation can still differ because of Scottish rates.
If you pay payments on account, the January payment often includes both the balancing payment and the first instalment toward the next year. Plan cash for both.
People using Making Tax Digital for Income Tax still send a Self Assessment return and pay by 31 January 2027.
How Marsal Accountants can help
- Self Assessment preparation and filing
- A check of whether the paper, online, or coding-out date applies to you
- Bookkeeping that makes next year’s return easier to support
Contact us for a free consultation, or see our Self Assessment tax returns service.
