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Paper tax returns are due by 31 October. The three Self Assessment dates that follow

If you file your 2025 to 2026 tax return on paper, HMRC must have it by 11:59pm on Saturday 31 October. Online filers have until 31 January 2027, with an earlier date if you want to pay through your tax code.

Published 25 October 2026Last checked 25 October 2026UK-wideFrom HM Revenue and Customs

A postbox at dusk with a single brown envelope half posted in its slot, autumn leaves gathered at its base and a streetlamp glowing nearby.

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What's happening

Your Self Assessment tax return for the 2025 to 2026 tax year must reach HMRC by 11:59pm on 31 October 2026 if you send it on paper, or by 11:59pm on 31 January 2027 if you file online. If you file online by 30 December and owe less than £3,000, HMRC can collect the tax through your tax code instead of in one go. Missing a deadline costs £100 straight away, even if you owe no tax.

The question: When do I need to send my 2025 to 2026 Self Assessment tax return, and what happens if I miss the date?

This applies to you if…

  • You were self-employed as a sole trader and earned more than £1,000 before expenses
  • You were a partner in a business partnership
  • You had to pay Capital Gains Tax, for example on crypto gains above the £3,000 tax-free allowance
  • You had to pay the High Income Child Benefit Charge and do not pay it through your wages
  • HMRC has asked you to send a return

Not for you if…

  • People whose only income is from a job or pension taxed through PAYE, unless HMRC has asked for a return
  • Anyone who has already filed their 2025 to 2026 return

What it's worth

What it's worth: £100 penalty avoided, rising to £1,300 or more if a return is six months late

HMRC late filing penalties, 2025 to 2026 tax return, UK-wide

Tax year 2025 to 2026 (6 April 2025 to 5 April 2026)

Illustrative calc: what a late return can cost

  1. One day late: £100 penalty.
  2. Three months late: £10 a day for up to 90 days, which is up to £900 more.
  3. Six months late: a further 5% of the tax due or £300, whichever is greater.
  4. For someone who owes £2,000 in tax, 5% is £100, so the £300 applies.
  5. £100 plus £900 plus £300 comes to £1,300.

Up to £1,300 in filing penalties after six months, before any late payment penalties or interest

Illustrative only, using HMRC's published penalty rules. Late payment penalties and interest are charged separately.

How to do it

  1. 1

    Check whether you need to file

    Use HMRC's list of who must send a tax return. If HMRC has written asking for a return, you need to send one.

    Takes about 5 minutes

  2. 2

    Choose paper or online

    The paper form is the SA100. It must reach HMRC by 11:59pm on 31 October 2026, so allow time for post.

  3. 3

    If filing online, sign in early

    You need Government Gateway sign-in details and may need to prove your identity with photo ID such as a passport or driving licence.

    Takes about 20 minutes

  4. 4

    Check any pre-filled figures

    Online returns may already show some figures, such as a Winter Fuel Payment charge or Child Benefit. Check they are right and add them if missing.

  5. 5

    File and pay

    File online by 30 December 2026 if you want tax under £3,000 collected through your tax code. Otherwise file and pay by 31 January 2027.

Deadline

Paper returns for 2025 to 2026 must reach HMRC — 31 October 2026 (in 6 days)

11:59pm on Saturday 31 October 2026. Online filers have until 31 January 2027.

The catches

Penalties apply even with no tax to pay

The £100 late-filing penalty is charged if your return is late, even if you owe nothing or are due a refund.

The tax code route has limits

You must owe less than £3,000, already pay tax through PAYE (for example as an employee or with a company pension), and file online by 30 December or on paper by 31 October. You cannot make a part payment to get under £3,000.

Paper filers add some figures themselves

If you got the 2025 Winter Fuel Payment and your income was over £35,000, you must add the repayment yourself on a paper return. Online it is pre-filled where possible.

Late payment costs extra

If you pay late, HMRC charges 5% of the unpaid tax at 30 days, 6 months and 12 months, plus interest.

Scam messages rise near deadlines

HMRC never sends tax rebate notices by text message. Do not click links in unexpected messages or share your HMRC sign-in details.

Illustrative example

Illustrative example: a retired landlord

Pat is 68, gets a company pension taxed through PAYE and rents out a flat. Pat's tax on the rent for 2025 to 2026 comes to £1,400.

  1. Pat must file a return because of the rental income.
  2. Pat files online on 12 December 2026, before the 30 December date.
  3. Pat owes less than £3,000 and already pays tax through a company pension, so HMRC can collect the £1,400 through Pat's tax code.
  4. Pat avoids one large payment on 31 January 2027.

Pat spreads the bill through the pension instead of paying it in one go.

Illustrative only. Your figures and options depend on your own income and tax.

What this means for…

  • Self-employed: Sole traders with more than £1,000 of income before expenses must file.
  • Landlord: Rental income above certain limits means filing. Tax under £3,000 can go through your tax code if you also have PAYE income and file online by 30 December.
  • Retired: If you got the 2025 Winter Fuel Payment and your income was over £35,000, the repayment goes on your return.
  • Higher-rate taxpayer: If you pay the High Income Child Benefit Charge and do not pay it through PAYE, you must file. HMRC pre-fills Child Benefit details for around 300,000 people.

Common misreadings

You might hear: If I owe no tax, a late return does not matter.

Actually: The £100 penalty applies to a late return whether or not you owe tax.

You might hear: The 31 October date applies to everyone.

Actually: It is the deadline for paper returns. Online returns are due by 31 January 2027.

You might hear: Anyone can have their tax bill collected through their tax code.

Actually: Only if you owe less than £3,000, already pay tax through PAYE, and file in time (online by 30 December or on paper by 31 October).

Where the UK nations differ

UK-wide
The deadlines and penalties are the same across the UK. Scottish and Welsh taxpayers use the same return, though income tax rates differ in Scotland.

What you could do

  1. still plan to file on paper

    Post your SA100 so HMRC receives it by 11:59pm on 31 October 2026, or switch to filing online by 31 January 2027.

    By 2026-10-31

  2. owe less than £3,000 and get a wage or company pension

    File online by 30 December 2026 so HMRC can collect the tax through your tax code.

    By 2026-12-30

  3. got the 2025 Winter Fuel Payment and had income over £35,000

    Check the Winter Fuel Payment charge is on your return. Add it yourself on a paper return.

    By 2027-01-31

Timeline

  1. 5 October 2026

    Deadline to register for Self Assessment

    If you register late, tax is still due by 31 January 2027.

  2. 31 October 2026

    Paper returns due

    11:59pm.

  3. 30 December 2026

    File online by this date to pay through your tax code

    For bills under £3,000.

  4. 31 January 2027

    Online returns due and tax to pay

    11:59pm.

  5. 31 July 2027

    Second payment on account

    Only if you make payments on account.

The detail

The rules

  • Tax year covered: 6 April 2025 to 5 April 2026.
  • Paper returns must reach HMRC by 11:59pm on 31 October 2026. Online returns by 11:59pm on 31 January 2027.
  • Tax owed must be paid by 11:59pm on 31 January 2027.
  • To pay through your tax code: owe less than £3,000, already pay tax through PAYE, file online by 30 December 2026 or on paper by 31 October 2026.
  • Late filing: £100, then £10 a day after 3 months (up to £900), then 5% or £300 after 6 months and again after 12 months.
  • Late payment: 5% of unpaid tax at 30 days, 6 months and 12 months, plus interest.

References

  • HMRC press release, 23 October 2026: Around 12 million people expected to file by 31 January 2027.
  • GOV.UK, pay through your tax code: Bills under £3,000 only; no part payments to get under the limit.

Documents

Words explained

Self Assessment
HMRC's system for people to report income that is not fully taxed through wages or pensions.
SA100
The main paper tax return form.
PAYE (Pay As You Earn)
Tax taken from wages or a pension before you are paid.
Tax code
A code that tells your employer or pension provider how much tax to take from your pay.
Payment on account
Advance payments towards next year's tax bill, due in January and July.

In short

Paper tax returns for 2025 to 2026 must reach HMRC by 11:59pm on 31 October. Online, the deadline is 31 January 2027. File online by 30 December and owe under £3,000, and you may be able to pay through your tax code. A late return costs £100, even with no tax to pay.

Related dates

  • 28 Oct Autumn Budget 2026Announcement · in 3 days
  • 31 Oct Paper Self Assessment return deadline (2025 to 2026)Deadline · in 6 days
  • 7 Nov Making Tax Digital: second quarterly update dueDeadline · in 13 days
  • 30 Dec File Self Assessment online to pay through your tax codeDeadline · in 66 days
  • 31 Jan Online Self Assessment return and payment deadline (2025 to 2026)Deadline · in 98 days
  • 7 Feb Making Tax Digital: third quarterly update dueDeadline · in 105 days
See the money calendar

Sources

  1. Self Assessment tax returns: deadlines, GOV.UK (2026-10-25)
  2. Pay your Self Assessment tax bill through your tax code, GOV.UK
  3. Self Assessment tax returns: penalties, GOV.UK
  4. Who must send a tax return, GOV.UK
  5. Self Assessment deadline incoming: 100 days to go, HMRC (2026-10-23)
  6. Self Assessment tax return (SA100), HMRC
  7. Reporting fraudulent emails and texts, HMRC

This is guidance, not regulated financial advice. Check figures against the linked official source before you act. Written with AI assistance and checked against primary sources. How Kitty works. For free, impartial help, try MoneyHelper or Citizens Advice.