Self Assessment deadline 31 January 2027: what to file and pay
By 11:59pm on 31 January 2027 you file your 2025/26 return online and pay the tax you still owe, plus the first payment on account for 2026/27. Miss it and the penalty starts at £100. The full deadline calendar, a worked example for a sole trader and what to do if you are late.
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The deadline for your 2025/26 Self Assessment tax return is 11:59pm on 31 January 2027 if you file online. By the same time you must pay all tax you still owe for 2025/26 and, for most people who pay tax this way, the first payment on account for 2026/27.
Law as of 12 November 2026
The return is required under the Taxes Management Act 1970 s. 8 after notice to HMRC under s. 7. Payments on account are set by TMA 1970 s. 59A and the final payment by s. 59B. Late filing penalties are in Finance Act 2009 Schedule 55, late payment penalties in Schedule 56.
The deadlines for the 2025/26 tax year
The return covers the tax year from 6 April 2025 to 5 April 2026.
| Date | What is due |
|---|---|
| 5 October 2026 | Register for Self Assessment if you are new or did not file for 2024/25 |
| 31 October 2026 | Paper return |
| 30 December 2026 | Online return, if you want a bill under £3,000 collected through your tax code |
| 31 January 2027 | Online return; the balance of your 2025/26 tax; the first payment on account for 2026/27 |
| 31 July 2027 | Second payment on account for 2026/27 |
| 31 January 2028 | Last day to correct your 2025/26 return |
Every deadline ends at 11:59pm. Legal basis: TMA 1970 ss. 8, 59A and 59B.
If you missed the paper deadline, file online. If you registered after 5 October 2026, HMRC sends you a letter or email with your own filing deadline, 3 months from its date, but the tax is still due by 31 January 2027.
What you file on 31 January
One return for all your income in 2025/26 that was not fully taxed at source. You need one if, for example:
- you were a sole trader with income over £1,000 before expenses;
- you received dividends over £10,000, as many company directors do (see Self Assessment for company directors);
- you had untaxed income such as rent or foreign income, a capital gain with tax to pay, or the High Income Child Benefit Charge not paid through PAYE;
- HMRC sent you a notice to file. Then you must file, even if you think you owe nothing.
Before you start, collect your Unique Taxpayer Reference (UTR), your sales and expenses for the year, your P60 if you were also employed, and the dividend and interest amounts you received.
What you pay on 31 January
On 31 January 2027 you pay two things:
- The balancing payment: your tax for 2025/26, minus any payments on account you already made for it.
- The first payment on account for 2026/27: half of your 2025/26 bill. The second half follows on 31 July 2027.
Payments on account include Class 4 National Insurance. You do not make them if your last bill was under £1,000, or if more than 80% of your tax was taken at source, for example through PAYE. Legal basis: TMA 1970 s. 59A.
Worked example: a sole trader's first January bill
Sam is a sole trader in England. His profit for 2025/26 is £40,000. It is his first return, so he made no payments on account for 2025/26.
- Profit above the Personal Allowance: £40,000 − £12,570 = £27,430.
- Income tax at the basic rate: £27,430 × 20% = £5,486.
- Class 4 National Insurance: £27,430 × 6% = £1,645.80.
- Class 2: his profit is above £6,845, so Class 2 is treated as paid and costs him nothing.
- His 2025/26 bill: £5,486 + £1,645.80 = £7,131.80.
| Date | Payment | Amount |
|---|---|---|
| 31 January 2027 | Balance of 2025/26 tax | £7,131.80 |
| 31 January 2027 | First payment on account for 2026/27 | £3,565.90 |
| 31 July 2027 | Second payment on account for 2026/27 | £3,565.90 |
On 31 January 2027 Sam pays £10,697.70, one and a half times his tax for the year. This first-year jump catches out many new sole traders.
If Sam had already paid £6,000 on account for 2025/26, his balancing payment would be £7,131.80 − £6,000 = £1,131.80, and on 31 January 2027 he would pay £1,131.80 + £3,565.90 = £4,697.70.
In Scotland the same profit is taxed at the Scottish rates for 2025/26: £2,827 × 19% + £12,094 × 20% + £12,509 × 21% = £537.13 + £2,418.80 + £2,626.89 = £5,582.82 income tax. Class 4 National Insurance stays £1,645.80, so the bill is £7,228.62.
How to pay on time
| Payment method | Time to reach HMRC |
|---|---|
| Online or telephone banking (Faster Payments), CHAPS, debit or corporate credit card online, approval through your online bank account | Same or next day |
| Bacs; Direct Debit you set up with HMRC before | 3 working days |
| Direct Debit you set up for the first time | 5 working days |
31 January 2027 is a Sunday. If you pay by Bacs, CHAPS or Direct Debit, the money must reach HMRC on the last working day before, Friday 29 January 2027. Faster Payments and card payments still count on the day. Your payment reference is your 10-digit UTR followed by the letter K.
You can also pay in weekly or monthly instalments before the deadline. If you cannot pay in full, contact HMRC early: you may be able to set up a payment plan, and HMRC checks that it is affordable for you.
If you miss the deadline
Filing late and paying late are penalised separately.
| Late | Penalty |
|---|---|
| Return 1 day late | £100 |
| Return 3 months late | £10 a day, up to £900 |
| Return 6 months late | 5% of the tax due or £300, whichever is greater |
| Return 12 months late | Another 5% or £300, whichever is greater |
| Tax 30 days late | 5% of the tax unpaid |
| Tax 6 months late | Another 5% of the tax unpaid |
| Tax 12 months late | Another 5% of the tax unpaid |
Legal basis: Finance Act 2009 Schedules 55 and 56. HMRC also charges interest on every late payment, payments on account included (TMA 1970 s. 86): 7.75% a year now and 8.00% from 24 November 2026 (Bank of England base rate plus 4%).
Example: Sam files and pays his £10,697.70 three weeks late, on 21 February 2027. He gets the £100 late filing penalty. He paid within 30 days, so there is no late payment penalty. Interest at 8.00% for 21 days: £10,697.70 × 8.00% × 21 ÷ 365 = £49.24, if the rate does not change. Had his 2025/26 tax still been unpaid after 30 days, a further £7,131.80 × 5% = £356.59 would follow.
These rules are for the 2025/26 return. If you joined Making Tax Digital for Income Tax on 6 April 2026, the new penalty points system applies from your 2026/27 return onwards.
Appealing a penalty
You can appeal if you had a reasonable excuse, usually within 30 days of the date the penalty was issued. HMRC accepts, for example, the death of a partner or close relative shortly before the deadline, an unexpected stay in hospital, or a computer or software failure while you were preparing your online return. It does not accept a failed payment because there was not enough money, finding the online system too hard, or not getting a reminder.
Norman in the UK
Norman is an AI bookkeeping app for small companies and sole traders. In Germany and Poland it is live today: it categorises bank transactions, reads receipts, writes invoices and prepares tax returns, and you review and approve every step. We are preparing Norman for the UK. Until then, our free UK guides are yours to use, no account needed, and here is more about Norman in the UK.
Frequently asked questions
When is the Self Assessment deadline for 2025/26?
11:59pm on 31 January 2027 for an online return and for paying the tax. The paper deadline was 31 October 2026.
What happens if I miss the 31 January deadline by one day?
HMRC charges a £100 late filing penalty, and interest runs on any tax you have not paid. If the tax is paid within 30 days, there is no late payment penalty yet.
Why do I have to pay more than my tax bill in January?
Because the first payment on account for the next tax year, half of this year's bill, is due on the same day. You do not make payments on account if your bill was under £1,000 or more than 80% of your tax was taken at source.
The deadline is on a Sunday. Do I get until Monday?
No. File online by 11:59pm on Sunday 31 January 2027. If you pay by Bacs, CHAPS or Direct Debit, the money must reach HMRC by Friday 29 January 2027; Faster Payments and card payments count on the day.
Can I correct my return after I have filed it?
Yes. You can correct your 2025/26 return within 12 months of the deadline, so usually until 31 January 2028.