Guides › Do I Need to File a Self Assessment Return for 2025-26?

Do I Need to File a Self Assessment Return for 2025-26?

Short answer: GOV.UK lists when you must send a return for the last tax year (6 April to 5 April). If HMRC wrote asking you to file, you must, by the deadline on the letter. GOV.UK also has an official check tool (it does not send your details to HMRC).

You must send a return if, in the last tax year:

• you were a sole trader and earned more than £1,000 (before deducting anything you can claim tax relief on);
• you were a partner in a business partnership;
• you had to pay Capital Gains Tax on selling or disposing of something that increased in value;
• you had to pay the High Income Child Benefit Charge and don't pay it through PAYE;
• you're an off-payroll worker repaying a student or postgraduate loan.

You may also need to file for untaxed income, such as

rent from property or land, tips and commission, savings interest, dividends (including investments), foreign income, or any taxable UK income if you're a non-UK resident. GOV.UK also says additional income, for example selling things online or renting out part of your home, may need telling to HMRC.

You can choose to file to

prove you're self-employed (for example for Tax-Free Childcare or Maternity Allowance), pay voluntary National Insurance contributions, or claim relief on maintenance payments.

If you think you no longer need to file

GOV.UK says you'll need to contact HMRC and explain; the HMRC app page says you can now use the app to tell HMRC you no longer need to send a tax return (added 17 February 2026).

Steps

1. Run GOV.UK's check tool for the 2025 to 2026 tax year.
2. If yes: register by 5 October if new (dates); file by 31 January 2027.
3. If unsure, ask HMRC or an adviser.

FAQ

I'm employed and have a side hustle of £800. The £1,000 sole trader figure in GOV.UK's list is the test it gives for self-employment; other rules (and other income) may still apply. Use the tool.

Do I need a return if I'm in MTD? Yes for 2025-26: see MTD vs Self Assessment.

What we could not verify

• Your personal circumstances; the tool and HMRC decide.
• Detailed rules for each category (follow GOV.UK links).

Sources (GOV.UK)

• GOV.UK, Self Assessment tax returns: Who must send a tax return — https://www.gov.uk/self-assessment-tax-returns/who-must-send-a-tax-return (read 17 October 2026)
• GOV.UK, Check if you need to send a Self Assessment tax return — https://www.gov.uk/check-if-you-need-a-tax-return (read 17 October 2026)
• GOV.UK, Download the HMRC app (page last updated 7 September 2026) — https://www.gov.uk/guidance/download-the-hmrc-app (read 17 October 2026)
• GOV.UK, Self Assessment tax returns: Overview — https://www.gov.uk/self-assessment-tax-returns/if-you-no-longer-need-to-send-a-tax-return (read 17 October 2026)

Deadlines calendar → Penalty estimator →

Not tax advice. See the disclosure.