Self Assessment and Tax Deadlines 2026 to 2027
Key UK tax dates for the 2025/26 Self Assessment return and the 2026/27 tax year, with free email reminders.
2026/27 rates · verified 11 October 2026
| Date | What's due | |
|---|---|---|
| 5 October 2026 | Register for Self Assessment for 2025/26 if you need to file and haven't before | |
| 31 October 2026 | Paper tax returns for 2025/26 must reach HMRC | |
| 30 December 2026 | File online by now to have tax under £3,000 collected through your tax code | |
| 31 January 2027 | Online tax return deadline for 2025/26; pay the balance and first payment on account for 2026/27 | |
| 5 April 2027 | End of the 2026/27 tax year: last day to use ISA, pension and CGT allowances | |
| 6 April 2027 | Start of the 2027/28 tax year: new rates and thresholds apply | |
| 31 May 2027 | Employers give employees their P60 for 2026/27 | |
| 31 July 2027 | Second payment on account for 2026/27 |
Who needs to file a tax return?
You need to send a Self Assessment return if, in the last tax year, you were self-employed and earned more than £1,000, were a partner in a business partnership, had Capital Gains Tax to pay, had to pay the High Income Child Benefit Charge and don't pay it through PAYE, or had untaxed income such as rent, tips, savings interest or dividends above your allowances.
Frequently asked questions
When is the Self Assessment deadline?
31 January 2027 for online returns for the 2025/26 tax year, which is also when you pay any tax owed. Paper returns were due by 31 October 2026.
What happens if I miss the deadline?
An immediate £100 penalty for filing late, even if you owe no tax, rising after 3, 6 and 12 months. Interest is charged on late payments.
What are payments on account?
Advance payments towards next year's bill, each half of your previous year's bill, due on 31 January and 31 July. You don't make them if your last bill was under £1,000 or more than 80% of your tax was already collected at source, for example through PAYE.
When does the tax year end?
The 2026/27 tax year runs from 6 April 2026 to 5 April 2027.
Related calculators
All rates, thresholds and dates on this page come from official sources, including GOV.UK, HM Revenue and Customs, the Scottish Government, Revenue Scotland and the Welsh Government. Last verified 11 October 2026.