Small Business Guides / starting a business in the UK

Do I Need to Register as Self-Employed in the UK?

Check whether your activity is a trade and whether you need to register for Self Assessment. Starting a small side business does not mean the paperwork can be ignored.

Check gross trading income first

HMRC’s guidance generally requires registration when gross trading income exceeds £1,000 in a tax year. Gross income means receipts before deducting expenses. There are exceptions and other reasons to register, so use HMRC’s current guidance rather than treating the allowance as a complete answer.

Registration is not the same as tax owed

You may need to report income even if allowances or expenses mean little tax is payable. Conversely, having a small business does not mean a customer can decide your employment status simply by asking you to send invoices.

The usual notification deadline is 5 October following the relevant tax year. Check your position if you have filed before, have missed a deadline, work under special industry arrangements or have other untaxed income.

What to prepare

1. Write down when you started and what you sell.
2. Total all relevant trading receipts for the tax year.
3. Keep evidence of costs and other income.
4. Check whether you are already registered and whether your records need updating.
5. Use the official HMRC registration route and retain confirmation.

Keep the wider setup moving

Registration does not replace insurance, permissions, banking or a way to keep records. Complete the jobs that apply to your actual activity before accepting work.

Compare sole trader and limited-company structures, follow the admin setup checklist and use the invoice template when you are ready to bill a customer.

Explore Polar’s business tools or the connected business software for the next practical step.