Self Assessment deadlines (2025/26 return)

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

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

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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.

GOV.UK sources (checked 15 October 2026):

Related

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.

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