Registration as a sole trader is simpler than many people expect, but the timing rules matter. Miss the deadline and HMRC can charge a penalty. Fail to register at all and you risk mounting penalties on unpaid tax. Most people can complete the process online in under 30 minutes once they have the right information to hand.
Written and reviewed by James Whitfield · Updated August 2026 · Checked against 2026/27 HMRC rates · Editorial standards · Methodology
You must register as a sole trader with HMRC once your gross trading income tops £1,000 in a tax year, and the deadline is 5 October after the tax year you started.1 Registration is online, takes 15–30 minutes, and needs your National Insurance number and basic business details.2 HMRC then posts your Unique Taxpayer Reference (UTR) within about 10 working days — you need it to file. Miss the deadline and there can be a penalty based on the tax owed, so register as soon as you cross £1,000.
Registration is quick if you have the details to hand before you start. Everything below goes into HMRC's online 'register as self-employed' process.
| National Insurance number | Required |
| Date you started trading | Required |
| Business name (if not your own name) and activity | Required |
| Contact details and home/business address | Required |
| Government Gateway account | Created during registration |
You must register as self-employed with HMRC if your gross trading income — the total amount earned from self-employment before any expenses are deducted — exceeds £1,000 in a tax year. This is the trading allowance threshold. Below £1,000 gross, no registration is required and no Self Assessment return is needed on the basis of that trading income alone.
The deadline for registration is 5 October following the end of the tax year in which you started trading. The tax year runs from 6 April to 5 April. If you started trading at any point between 6 April 2026 and 5 April 2027 and your gross income exceeded £1,000, you must register by 5 October 2027. If you miss this deadline, HMRC can charge a penalty — typically a percentage of the unpaid tax, though the penalty is waived if there is nothing to pay.
The £1,000 threshold is based on gross income from trading, not profit. A sole trader who earns £1,500 in fees but has £800 in expenses still needs to register even though their profit is only £700 — their gross trading income exceeds £1,000. The trading allowance cannot be applied to reduce registration liability, only to calculate whether tax is owed.
Registration is done online via GOV.UK by completing the 'Register as self-employed' process under HMRC's self-employment section. You will need a Government Gateway account — if you do not have one, you create it during the registration process. You will need: your National Insurance number; your date of birth; your business name (if you trade under a name other than your own); the date you started self-employment; a description of your business activity; and your contact details and address.
If you are using a business name, note that sole traders can trade under any name subject to restrictions — you cannot use 'Ltd' or 'PLC' (those imply limited company status), and you cannot use a name that implies government or public sector affiliation. You do not need to register your business name at Companies House. It is simply the trading name on your invoices.
After registering online, HMRC posts a Unique Taxpayer Reference (UTR) to your home address within approximately 10 working days. This is a 10-digit number you will use for all future correspondence with HMRC, for filing your Self Assessment return, and for any dealings with your accountant. Keep it safe — you will need it annually.
Once HMRC has processed your registration, you will receive two things: your UTR by post, and activation of your Self Assessment account in your Government Gateway. Log in to your HMRC online account to verify the account is active and that your personal details are correct. HMRC may send a code to activate the Self Assessment section separately.
From the date you registered your start of trading, you are required to keep records of all business income and expenses. This is a legal obligation, not a suggestion. Records must be kept for at least five years after the 31 January filing deadline for the relevant year — for 2026/27 that means keeping records until at least 31 January 2033. Digital records including photographs of receipts are acceptable.
Your first Self Assessment return will cover the tax year in which you registered. Even if you only traded for part of that year, the return must cover the full year. If you started trading in October 2026, your first return covers 6 April 2026 to 5 April 2027 and must be filed by 31 January 2028.
The most common late-registration scenario is a sole trader who starts earning modest side income, assumes the amounts are too small to matter, and then discovers that gross income exceeded £1,000 over the course of the year. The 5 October deadline passes without registration. HMRC's penalty for late registration is typically charged as a percentage of the tax unpaid at the time of the failure, with a minimum of £100 in some cases.
Not knowing your filing deadlines is a close second. Once registered, you must file your Self Assessment return by 31 January each year (for online filing) covering the previous tax year. Missing this results in an automatic £100 penalty, rising to £1,000 or more after three months of continued non-filing. HMRC does not individually remind you of the deadline — it is your responsibility to file on time.
A third common error is not activating the Self Assessment section of your Government Gateway promptly after registration. If you wait until January to try to file and find you cannot access your account, resolving it at that stage can take days. Set up the online account as soon as you receive your UTR and verify access before the filing season.
The online registration itself takes 15–30 minutes. After submitting, you receive your UTR by post within approximately 10 working days. Allow time for this before you need the UTR for any formal purpose.
No. HMRC does not require a business bank account for sole trader registration. However, having one makes bookkeeping significantly easier and is strongly recommended once income is regular.
Yes. HMRC accepts late registration. Register as soon as you realise you should have done so. The penalty, if any, is typically based on the amount of unpaid tax — if you have paid no tax because you owe none, the penalty may be zero.
Your NI number is on your National Insurance card, payslips from previous employment, HMRC correspondence, or your P60. If you cannot find it, HMRC's online service can help you trace it.
Register in the first tax year your gross trading income exceeds £1,000, even if that income was earned in just one or two months. The threshold is annual — it does not matter how evenly income was spread across the year.
The rates, thresholds and rules in this guide are drawn from the official HMRC and GOV.UK sources below, using the confirmed 2026/27 figures. Each link opens the relevant official page in a new tab.
The sole trader tax calculator turns this guidance into a concrete monthly take-home and tax reserve estimate, based on 2026/27 HMRC rates. Enter taxable profit — not turnover.
Self Assessment checklist, expense tracker and payments on account calendar — all in one practical PDF. Updated for 2026/27.
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