Guide
Paper Self Assessment deadline: 31 October 2026 for tradespeople
Shaun Holmes
The 31 October 2026 paper Self Assessment deadline for the 2025 to 2026 tax year, who still files on paper, what to do if you miss it, and the penalties in plain terms.
HMRC must receive a paper Self Assessment return for the tax year 6 April 2025 to 5 April 2026 by 11:59pm on 31 October 2026. That date is a Saturday. The rule is received, not posted. An online return has until 11:59pm on 31 January 2027. The printable list of what to gather is the Self Assessment checklist.
The dates below were read from GOV.UK on 18 October 2026. None of the links are affiliate links. This is general information, not advice for your own return. If the year includes a student loan, a capital gain, or a mix of PAYE and self-employment, ask an accountant or use the HMRC page. A chat tool can turn the dates into a list. It cannot file the return, and it cannot tell you the bill.
I've spent over 20 years in UK construction, and I still treat a paper form as late if it is sitting in the van on the Saturday. We search the AI world every week so you don't have to. The clock is HMRC's. The figures on the return are yours.
Who the 31 October date is for
HMRC's deadlines page (opens in a new tab) says the last tax year started on 6 April 2025 and ended on 5 April 2026. HMRC must receive a paper tax return by 11:59pm on 31 October 2026 or you get a late filing penalty. You can send it on or after 6 April 2026, as long as it arrives by that time.
The page for completing this year's return (opens in a new tab) says 97% of people already file online. Paper is still a route. If you live in the UK, you post it to Self Assessment, HM Revenue and Customs, BX9 1AS. If you live outside the UK, that page gives Benton Park View, Newcastle Upon Tyne, NE98 1ZZ.
You get a paper SA100 by downloading it or by asking HMRC to send one. The forms page (opens in a new tab) says both. The ordering page (opens in a new tab) is the phone line, and it says HMRC does not supply blank forms to agents. The short tax return, the SA200, is only if HMRC sends it to you. You cannot download it.
A sole trader is not in the group whose paper deadline is 31 January. The deadlines page says trustees of a registered pension scheme, and non-resident companies, cannot file online. Their paper return is due by 31 January 2027. That is a different return from a tradesperson's SA100.
If the income is self-employment, the SA100 needs the self-employment pages as well. Which set, and the records behind them, is in the first return guide. What HMRC allows you to deduct before a profit exists is in the allowable expenses guide.
Get it free every week
A weekly email on tax dates, invoices and the paperwork that follows a job.
If 31 October is going to be missed
The completion page (opens in a new tab) says that if you miss the paper filing deadline, you send the return online instead to avoid a penalty. The 2026 notes linked from that page (opens in a new tab) say that if you miss the paper deadline, you must send it online by 31 January 2027, or 3 months after the date on your notice to file if that is later. The deadlines page (opens in a new tab) puts the online time at 11:59pm on 31 January 2027.
Posting the paper form in November does not use that later date. The notes treat a missed paper deadline as a switch to online, not as extra time on paper.
The tax is still due by 11:59pm on 31 January 2027. Filing the paper form in October, or filing online in November, does not bring the payment forward and it does not push it back. If you make payments on account, there is a second payment date of 31 July. How those two payments are worked out, including on a first return, is in the payments on account guide.
If you want the bill collected through a tax code, the deadlines page says the online return has to be in by 11:59pm on 30 December 2026. A paper return for that route had to be received by 31 October. The conditions, including the £3,000 limit and the PAYE test, are in the 31 January 2027 guide.
If you register after 5 October 2026, the deadlines page says HMRC sends a letter or email with a filing deadline three months from the date on it. The payment date does not move. You still pay by 11:59pm on 31 January 2027.
You need a Unique Taxpayer Reference and sign-in details before the online service will take a first return. That setup is in the first return guide. Do not paste a UTR, a National Insurance number, or a password into a chat.
The penalties, in plain terms
HMRC's penalties page (opens in a new tab) sets the late filing charges:
- an initial £100 penalty
- after 3 months, £10 a day, up to a maximum of £900
- after 6 months, a further penalty of 5% of the tax due or £300, whichever is greater
- after 12 months, another 5% or £300, whichever is greater
The 2026 notes say that £100 is charged even if you do not owe any tax. The penalties page says you pay a penalty within 30 days of the date on the notice. If you have a reasonable excuse, you can appeal. The page does not list the excuses, so I am not going to invent one.
Late payment is a separate set of charges. The same page says penalties of 5% of the tax unpaid at 30 days, at 6 months, and at 12 months, plus interest on the amount owed. The interest rate moves, so I am not copying a percentage onto this page. The payments guide links the rates page.
A filing penalty does not replace the tax. You still send the return, and you still pay what is owed.
A short checklist before you post, or before you switch
This is the paper job for the 2025 to 2026 return. The longer tick-list, including records, CIS deductions, and payments on account, is the Self Assessment checklist.
- The tax year on the form is 6 April 2025 to 5 April 2026
- The form is the SA100, plus the supplementary pages that income needs, including self-employment
- The 10-digit UTR and the National Insurance number are on the form, not in a chat
- The form is signed and dated. The 2026 notes say you must sign it
- Receipts and accounts stay in your records unless HMRC has asked for them. The notes say sending them delays the return
- If you live in the UK, the envelope is addressed to Self Assessment, HM Revenue and Customs, BX9 1AS
- HMRC will have received it by 11:59pm on Saturday 31 October 2026. If it will not arrive by then, file online by 11:59pm on 31 January 2027
- The tax, and any payment on account on the statement, is still a 31 January 2027 payment
Turn these HMRC dates into a checklist for a paper Self Assessment return. UK English. Use only the dates and the address I type. Do not add a date. Do not say the paper form can arrive after 31 October. Do not say I can pay through a tax code.
Tax year:
Paper return must be received by:
Where I post it if I live in the UK:
If that date will be missed, I file online by:
Tax due by:
Read the list against the deadlines page and the 2026 notes. If a date has moved, use HMRC's page. The checklist above is the one I would tick. It is not a calculation of your bill.
Common questions
When is the paper Self Assessment deadline for 2025 to 2026?
HMRC's deadlines page says a paper return must be received by 11:59pm on 31 October 2026. The tax year ran from 6 April 2025 to 5 April 2026. An online return is due by 11:59pm on 31 January 2027, which is also when the tax is due.
What if I miss 31 October 2026?
HMRC's page for completing this year's return says you send the return online instead, to avoid a penalty. The 2026 notes say that online return must be in by 31 January 2027, or three months after the date on the notice to file if that is later. Posting the paper form after 31 October does not use the later date. The payment date stays 31 January 2027.
What is the late filing penalty?
HMRC's penalties page starts with £100. After 3 months it is £10 a day, up to £900. After 6 months it is 5% of the tax due or £300, whichever is greater, and the same again after 12 months. The 2026 notes say the £100 applies even if no tax is owed. Late payment is a separate 5% charge at 30 days, 6 months and 12 months, plus interest. A reasonable excuse can be appealed. The page does not list the excuses.
Get it free every week
Free when you sign up: the UK Trades AI Prompt Pack, with prompts for quotes, chasing payment, tax admin, and customers.