In short
You register as self-employed by registering for Self Assessment on gov.uk, which is free. You must register by 5 October after the end of the tax year in which you started (for example, by 5 October 2027 if you started between 6 April 2026 and 5 April 2027). HMRC then sends you a Unique Taxpayer Reference (UTR).
1. Check whether you need to register
You generally need to register if you earned more than £1,000 from self-employment in a tax year (6 April to 5 April). Below that, the trading allowance usually means you do not need to tell HMRC — though you may still choose to register, for example to pay voluntary National Insurance. Use HMRC’s check if you need to fill in a Self Assessment tool if you are unsure.
You can be employed and self-employed at the same time. Your job’s tax stays on PAYE; you register separately for your self-employed income.
2. Register for Self Assessment
Register on gov.uk at register for Self Assessment if you are self-employed. You will need a Government Gateway account, which you can create as part of the process. Have ready:
- Your National Insurance number
- Your personal details and address
- The date you started working for yourself
- What your business does and its address (your home is fine)
The deadline is 5 October after the end of the tax year in which you started. Registering late can lead to a penalty if it means tax is paid late, so do it as soon as you start trading.
3. Get your UTR
After you register, HMRC sends your Unique Taxpayer Reference (UTR) — a 10-digit number — by post, and it can also appear in your HMRC app or online account. It can take a few weeks. You need your UTR to file returns, and some customers or platforms may ask for it. See find your UTR.
4. Set up your record keeping
HMRC requires you to keep records of your business income and expenses. You must keep them for at least 5 years after the 31 January submission deadline for that tax year.
- Every payment you receive — including payouts from apps
- Receipts for what you spend on the business: supplies, tools, travel, insurance, phone
- Bank statements — a separate account for the business makes this much easier
- Mileage, if you claim simplified expenses for a vehicle
Making Tax Digital for Income Tax is being phased in: from April 2026 sole traders with qualifying income above £50,000 must keep digital records and send quarterly updates, with the threshold falling in later years. Check whether it applies to you.
5. File your tax return and pay
Online returns are due by 31 January after the end of the tax year, and that is also when the tax is due. Paper returns are due earlier, by 31 October. See Self Assessment deadlines and our guide to self-employed tax.
Questions people ask
How long does it take to register as self-employed?
The online form takes a short time to complete. Your UTR then arrives by post, which can take a few weeks, so do not leave it until just before the deadline.
Does it cost anything to register as self-employed?
No. Registering for Self Assessment with HMRC is free. Be wary of websites that charge to do it for you.
What is the deadline to register as self-employed?
By 5 October after the end of the tax year in which you started. The tax year runs from 6 April to 5 April.
Do I need to register if I earn under £1,000?
Usually not. The £1,000 trading allowance means you generally do not need to register or pay tax on self-employed income below that, unless you need a return for another reason.
Can I be employed and self-employed at the same time?
Yes. Your employer handles tax on your wages through PAYE, and you declare your self-employed income through Self Assessment.
Keep reading
Self-employed tax in the UK, explained plainly
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