Many people don’t rely on a single job or business to pay the bills. You might have a main trade or job but also run a side business, or earn occasional income from something completely different.
Not only is this a necessity, especially with the extraordinarily high cost of living, but it is also a way to spread risk.
One of the main questions people are asking is whether you have to register each activity as a separate business with HMRC.
You do not usually need a separate UTR for each self-employed activity. HMRC normally taxes you as one individual through Self Assessment, although very different trades may need to be shown separately on your tax return and kept apart in your records.
One UTR, one tax return
When you register as self-employed, HMRC issues you with a Unique Taxpayer Reference (UTR).
Your UTR number is unique to you. It is tied to your Self Assessment return rather than an individual activity.
You do not need to register each new business activity again, as all your sources of income are combined when you complete your SATR, or via MTD for Income Tax.
For a step-by-step overview, see our guide to the Self Assessment tax return, and HMRC’s official page on Self Assessment.
For example, if you make £30,000 profit from design work and £10,000 from selling second-hand clothes on Etsy, you do not have to submit two returns. You include both sets of figures on the same self-employment pages, and HMRC calculates your bill from the combined profit of both of your businesses.
If you accidentally register twice, read our article on what to do if you have duplicate UTRs.
When trades are kept separate
If your businesses are very different, HMRC may treat them as separate trades. A plumber who also runs a coffee shop would not usually mix those in a single set of accounts.
In cases like this, you would complete more than one set of self-employment pages in your return and keep clear records for each activity.
It is not an exact science, and means you need to use a bit of judgement to work out the best way to record your information. HMRC explains how it determines when a new trade begins in its Business Income Manual (BIM80505).
If you are unsure when your trade officially begins, read our guide on what counts as your business start date.
Keep your finances organised
- Bookkeeping – keep income and costs for each trade in their own ledger so you can see what is happening in each business.
- Bank accounts – using different accounts makes life easier, even if there’s no legal requirement to do so. See our guide to having multiple business bank accounts as a sole trader.
- Software – most accounting tools let you tag transactions by project or business line, so there is a clear distinction between your different businesses when it comes to tax time.
- Making Tax Digital for Income Tax (MTD) – from April 2026, higher earners with combined gross income over £50,000 must keep digital records and submit quarterly updates to HMRC. If you have multiple distinct trades, you will generally need to send separate quarterly updates for each trade. This makes the clear separation of records even more important. Lower thresholds, £30,000 from 2027 and £20,000 from 2028, will follow. See the joining deadlines here.
- Records – you have a responsibility to maintain accurate records. Read more in HMRC’s guidance on keeping business records if you are self-employed.
Other things to watch
- Trading allowance – the £1,000 allowance is per person, not per business. Running several ventures does not give you multiple allowances.
- Loss relief – if one trade makes a loss, you can usually offset it against profits from another trade, but only if your records clearly separate the figures.
- Insurance – ensure that your business insurance covers all activities you undertake. Policies often list specific occupations as well as exclusions.
- Extra paperwork – more business streams mean more invoices, receipts and paperwork. Make sure you set aside enough time to keep on top of your records.
Should you use a limited company instead?
Keeping everything under one sole trader setup is usually fine as long as the businesses remain small and manageable.
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If both are growing, or if you require a clear separation for legal or financial reasons, a limited company may be a better option. Each company is a separate legal entity, so profits and liabilities do not overlap. As a sole trader, all income ultimately belongs to you and is taxed as your personal earnings.
Read our comparison guide to sole trader vs. limited company for more differences between each business type.
Getting advice
Running more than one business can make your accounting tasks more challenging to manage, especially if you need to file quarterly updates for MTD for Income Tax.
If you are not sure how to split records between different trades or whether HMRC will expect you to report different business streams separately, an accountant can guide you.
Hiring an accountant is often one of the wisest moves small business people make. Using online accounting software is also a no-brainer and mandatory if you have to comply with MTD.
