Registering as Self-Employed

When and how to register for Self Assessment as a sole trader, and what happens in your first year.

Reviewed against official HMRC guidance

Tax year
2026/27
Last reviewed
August 2026
Reading time
8 min

When registration may be required

Who this guide is for: For people starting a sole trade or side hustle who need to know whether to tell HMRC, and what happens next.

  1. Step 1Gross trading income
  2. Step 2Register if required
  3. Step 3Receive UTR
  4. Step 4Keep records
  5. Step 5File and pay
Registration is the start of Self Assessment — not the tax bill itself.

Decision flow: £1,000 and below versus above

Plain-English starting point — confirm your case on GOV.UK.
Gross trading incomeTaxable trading profitTypical next step
£1,000 or lessFull Trading Allowance may mean £0 taxable profit from that tradeRegistration or reporting may still be required in some cases — do not assume you can ignore HMRC
Over £1,000Profit depends on expenses or allowance methodRegister for Self Assessment by 5 October after the tax year you started trading

Compare the allowance with actual costs in Trading Allowance Explained.

Registering versus Self Assessment versus paying

  • Registering as self-employed tells HMRC you have a trade and need a Self Assessment record.
  • Registering for Self Assessment is the broader process that issues your Unique Taxpayer Reference (UTR).
  • Receiving a UTR lets you file online and manage your account.
  • Filing a return reports income, expenses and allowances for the tax year.
  • Paying tax settles Income Tax and National Insurance that are due.

Tell HMRC you need to file by 5 October following the end of the tax year in which you started trading. For example, if you started between 6 April 2025 and 5 April 2026, register by 5 October 2026.

For online Self Assessment, file your return and pay any balancing amount by 31 January after the tax year ends. For 2026/27, that deadline is 31 January 2028.

What happens after you register?

  1. UTR — HMRC issues your Unique Taxpayer Reference.
  2. Online account — use Government Gateway / your Personal Tax Account to file.
  3. Record keeping — start from day one; see Business Records for Sole Traders.
  4. Annual return — file Self Assessment for each tax year you are required to.
  5. Payment deadlines — for 2026/27, file and pay online by 31 January 2028.
  6. Possible payments on account — advance January and July instalments if eligibility tests are met; see Self Assessment Payments on Account Explained.

Estimate Income Tax, National Insurance and first-year cash payments Use the Self-Employed Tax Calculator

Employed and self-employed together

PAYE on employment does not remove the need to report a trade through Self Assessment when registration rules apply. Tax already collected at source can affect whether payments on account are required.

Frequently asked questions

Do I need to register if I earn less than £1,000?

Gross trading income of £1,000 or less may be covered by the full Trading Allowance so that no trading profit is taxable. That does not automatically mean you can ignore HMRC — you may still need to register or report in some circumstances. Check GOV.UK for your situation.

Is the registration threshold based on turnover or profit?

The common Self Assessment trigger for trading is based on gross trading income (turnover), not profit after expenses. Low profit with high turnover can still require registration.

What happens if I register late?

You should still register as soon as possible. Late registration or late filing can lead to penalties. Confirm current deadlines and penalty rules on GOV.UK.

Is registering the same as paying tax?

No. Registration gets you into Self Assessment. You still need to keep records, file a return and pay any tax and National Insurance that is due.

Official sources

Related calculators

Related guides

Next steps

This guide is for general information only. It is not tax, legal or financial advice. Always check the official guidance for your situation.