# Self Assessment deadlines 2026/27: 31 January 2027 and more

Source: https://kit.andreiturcea.com/guide-self-assessment-deadlines.html
Last updated: 2026-10-15 · Last checked against GOV.UK: 2026-10-15


**Short answer:** For the 2025/26 tax return: register by 5 October 2026, file a paper return by 31 October 2026, and file online and pay by 31 January 2027. The second payment on account is due by 31 July 2027.

Last updated: 15 October 2026 · Last checked against GOV.UK: 15 October 2026 · [Markdown version](https://kit.andreiturcea.com/guide-self-assessment-deadlines.html.md)

**General information, not tax or financial advice.** Check GOV.UK or speak to a qualified adviser about your own situation.

**Keeping your own records?** The UK Sole Trader Kit is a £9 spreadsheet for Google Sheets and Excel: an income log, expenses mapped to SA103 boxes, a live 2026/27 tax and Class 4 NI estimate, and an invoice template. [See what is inside](https://kit.andreiturcea.com/) · [Get the kit (£9)](https://turceapaul.gumroad.com/l/bmykeg)

| What | Deadline |
|---|---|
| Register for Self Assessment (new) | 5 October 2026 |
| Paper tax return | 31 October 2026 |
| Online tax return | 11:59pm, 31 January 2027 |
| Pay tax owed + 1st payment on account for 2026/27 | 31 January 2027 |
| 2nd payment on account | 31 July 2027 |

Miss the online deadline and you can get a late filing penalty. If you are in MTD for Income Tax, quarterly updates also apply: see the [MTD deadlines](https://kit.andreiturcea.com/guide-mtd-quarterly-deadlines.html).

**GOV.UK sources (checked 15 October 2026):**

- [https://www.gov.uk/self-assessment-tax-returns/deadlines](https://www.gov.uk/self-assessment-tax-returns/deadlines)
- [https://www.gov.uk/understand-self-assessment-bill/payments-on-account](https://www.gov.uk/understand-self-assessment-bill/payments-on-account)

**Related**

- [Payments on account explained](https://kit.andreiturcea.com/guide-payments-on-account.html)
- [Self-employed tax calculator](https://calcs.andreiturcea.com/self-employed-tax-calculator.html)
- [Allowable expenses](https://kit.andreiturcea.com/guide-allowable-expenses.html)

## Frequently asked questions

### When is the 2025/26 Self Assessment deadline?

Paper returns by 31 October 2026, online returns by 11:59pm on 31 January 2027, and any tax owed paid by 31 January 2027.

### When must I register for Self Assessment?

By 5 October after the end of the tax year you need to file for, for example 5 October 2026 for 2025/26.

### Is there a July payment?

Yes, if you make payments on account. The second payment is due by 31 July.

### I registered late. When is my deadline?

If you register after 5 October 2026, you must still pay what you owe by 31 January 2027.

**Want this in a spreadsheet?** If you would rather not build your own tracker, the UK Sole Trader Kit (£9, Google Sheets and Excel) logs income, maps expenses to SA103 boxes, estimates your 2026/27 Income Tax and Class 4 NI, reminds you about payments on account and includes an invoice template. It is a template, not advice, and the free guides here stay free. [See what is inside](https://kit.andreiturcea.com/) · [Get the kit (£9)](https://turceapaul.gumroad.com/l/bmykeg)

---
Disclaimer: estimates for information only, not financial, tax or legal advice.