- 2025-26 online returns and tax due 31 January 2027; file by 30 December 2026 to pay under £3,000 through PAYE.
- Payments on account: half of last year's bill on 31 January and 31 July if the bill was £1,000 or more.
- Late filing: £100, then £10 a day after three months, then 5% or £300 at six and 12 months.
Key dates for 2025-26 returns
| Date | What happens |
|---|---|
| 31 October 2026 | Paper return deadline (passed) |
| 30 December 2026 | File online by this date to have tax owed of less than £3,000 collected through your PAYE tax code, if you are employed or get a pension |
| 31 January 2027 | Online return due; pay the balance for 2025-26 and the first payment on account for 2026-27 |
| 31 July 2027 | Second payment on account for 2026-27 |
Payments on account
If your last self assessment bill was £1,000 or more, HMRC usually expects two advance payments towards the next year, each half of the previous year’s bill, due on 31 January and 31 July. You do not have to make them if more than 80% of your tax was collected at source, for example through PAYE. If your income has fallen, you can apply to reduce them, but you will pay interest if the reduction turns out to be too much.
Late-filing penalties
| How late | Penalty |
|---|---|
| 1 day | £100, even if there is no tax to pay |
| 3 months | £10 a day for up to 90 days (up to £900) |
| 6 months | 5% of the tax due or £300, whichever is higher |
| 12 months | A further 5% or £300, whichever is higher |
Late payment brings interest at the Bank of England base rate plus 4% and separate late-payment penalties. If you have a reasonable excuse, you can appeal a penalty.
How this fits with MTD for Income Tax
Making Tax Digital for Income Tax started on 6 April 2026, so it covers the 2026-27 tax year. The 2025-26 return due on 31 January 2027 is filed in the usual way, even if you are already sending quarterly updates. See MTD for Income Tax: quarterly updates.
For accountancy practices: the January crunch
January is when unfiled returns, missing records and payments on account all land together, this year alongside a February MTD quarterly update. Practices that move record-chasing and first drafts earlier, often to an offshore team, spend January reviewing instead of preparing. See outsourced accounting for UK practices.
Living in the UK with income in India? See the guide for Indians in the UK.
Sources
- GOV.UK: Self Assessment tax returns, deadlines
- GOV.UK: Self Assessment tax returns, penalties
- GOV.UK: Understand your Self Assessment tax bill, payments on account
- GOV.UK: Pay your Self Assessment tax bill through your tax code
Frequently asked questions
When is the self assessment deadline in 2027?
What is the penalty for filing self assessment late?
Can I pay my self assessment tax through my tax code?
Who has to make payments on account?
Please note: this guide is general information based on the rules as they stood on the review date above. Regulations and RBI/CBDT procedures change often — please get advice on your specific facts before acting.