How to Register as Self-Employed with HMRC

When you need to register — and why earlier is much better than later

You must register if you have earned more than £1,000 from self-employment in a tax year. That is the trading allowance threshold, and it is the line HMRC actually cares about. The official deadline is 5 October following the end of the tax year in which you started. Plenty of people treat that date as the moment to act. That is a mistake.

The problem with leaving it late is not the form. After you register, HMRC posts your Unique Taxpayer Reference to your home address, which can take up to 10 working days. Activating Self Assessment online may then require another posted activation code — another 7 working days. You cannot file a return without a UTR, and the online filing deadline is 31 January. Stack those postal delays against a January deadline and you can see how people who register in early October still end up scrambling. Register the week you start self-employment. There is no downside to registering early, and there is a very real downside to leaving it until the official deadline.

What you need before you start

You do not need much. Have your National Insurance number, date of birth, home address, and the date you started self-employment to hand. You will also be asked for a description of the business. This does not need to be elaborate — “freelance web development” is enough — and you are not locked into that specific activity for life. If you do not already have a Government Gateway user ID, you can create one during registration. That is the entire list. If you are waiting until you have a business plan, a logo, or a dedicated office, you are inventing requirements that do not exist.

The registration process

Go to gov.uk/register-for-self-assessment. The questions are straightforward. Submit the form. HMRC then sends your UTR to your home address within 10 working days. It is a 10-digit reference that never changes, and you should keep any letter that contains it. Lose it and you will spend longer getting a replacement than you spent registering in the first place.

Once the UTR arrives, log into Government Gateway and activate Self Assessment. This may require another posted activation code, which is another potential 7-day wait. If you are anywhere near a filing deadline, start the activation the day the UTR arrives. Do not sit on the letter because January feels far away. The second postal wait is the one that catches people who thought they had already finished registering.

What tax you will pay — and when

You pay income tax on profit above the personal allowance of £12,570 in 2026/27 — 20% up to £50,270, 40% up to £125,140, and 45% above that. You also pay Class 4 National Insurance on profit: 9% between £12,570 and £50,270, and 2% above. Class 2 NI was abolished in April 2024, so Class 4 is the only National Insurance charge that remains for self-employed people. Both are paid through your annual Self Assessment, due by 31 January.

Tax	Rate	Applies to
Income tax	20% / 40% / 45%	Profit above £12,570
Class 4 NI	9% / 2%	Profit above £12,570

That is the short version. For bands, dividend rates, and everything else, see our complete UK tax rates guide for 2026/27.

The January shock — what first-time filers consistently miss

This is the most important section in the guide, and it is the one other registration articles treat as a footnote. When you file your first Self Assessment in January, HMRC collects not just the tax you owe for the year that has finished, but also a payment on account toward next year's bill. That is not a rounding error. It is a 50% surcharge on the number you thought you were paying.

There are two payments on account each year, in January and July, and each is equal to 50% of the previous year's tax bill. Worked example: your first tax bill is £6,000. The January payment is £9,000 — the £6,000 you actually owe, plus a £3,000 first payment on account. Another £3,000 follows in July. You have been saving for a £6,000 bill all year. You know the number. Then in January you owe 50% more than you expected.

This catches almost every first-time filer off guard. The standard recommendation for a sole trader is therefore to budget 25–30% of gross income from the start — not the lower percentage that would cover only the current year's bill. If you save just enough for this year's tax, January will hurt. If you save a third as you go, January is unpleasant but survivable.

VAT — a separate registration entirely

Self-employment registration and VAT registration are completely separate processes. Registering as self-employed does not make you VAT-registered. You must register for VAT separately if your taxable turnover exceeds £90,000 in any rolling 12-month period. Voluntary registration below £90,000 is worth considering if your clients are VAT-registered businesses who can reclaim the VAT you charge.

Sole trader or limited company — worth thinking about before you register

Registering as self-employed makes you a sole trader. The alternative is forming a limited company. For most people starting out, sole trader is the right default — simpler, cheaper, and at lower income levels often as tax-efficient as a Ltd, especially after the 2025 changes to dividend allowances and employer NI thresholds. A limited company typically starts making sense above £50,000–£60,000 profit, and only if your contracts are likely outside IR35 if you are contracting. You can always incorporate later if income grows. Starting as a sole trader does not close any doors, and it saves you from paying accountant fees on a structure you did not yet need.

If you have both employment and self-employment income

Having a day job alongside self-employment is extremely common, and it is entirely legitimate. Register for Self Assessment as self-employed; the return includes both your employment income (from your P60) and your self-employment profit, and HMRC calculates the combined tax position. The trap is the combined total. If income across both sources pushes you above £50,270, the marginal rate on your self-employment profit is 40%, not 20% — even if the self-employment income on its own would sit comfortably in the basic rate band. Your employer's PAYE does not account for this. The additional tax is collected through Self Assessment, which is how a side hustle that “only made £15,000” can produce a bill that feels nothing like 20%.

Record keeping — start as you mean to go on

From the moment you start, keep records of every business pound in and every business pound out. Invoices for everything you sell. Receipts for every expense you claim. A mileage log for work travel with the date, start point, destination, purpose and distance — HMRC expects that level of detail, and a log created retrospectively is obvious. Records must be kept for at least five years after the 31 January filing deadline for the relevant tax year. Digital records are fine.

Making Tax Digital for Income Tax requires sole traders above £50,000 to keep digital records and submit quarterly updates from April 2026, with the threshold dropping to £30,000 in 2027. If you are anywhere near those figures, start digital now rather than converting a year of paper in a panic. Our Making Tax Digital guide covers who is in, when, and what software actually has to do.

Frequently asked questions

How long does it take to register as self-employed?

The online form takes about 10 minutes. UTR arrives within 10 working days by post. There may be a further wait for an activation code for your Self Assessment account. Allow 3–4 weeks end-to-end before you can file a return.

Is registering as self-employed free?

Yes. The HMRC registration process costs nothing and is completed entirely online at gov.uk.

Can I be employed and self-employed at the same time?

Yes, and it's common. Declare both income sources on your Self Assessment return. HMRC calculates your combined tax position. Additional tax beyond what PAYE collected is due through Self Assessment.

What is a UTR and why do I need it?

A Unique Taxpayer Reference is a 10-digit number HMRC assigns when you register for Self Assessment. Required to file a return. Never changes. Keep any letter from HMRC containing it.

What happens if I earn less than £1,000 self-employed?

Below £1,000, the trading allowance means you don't need to register or pay tax on that income. Above £1,000, registration is required. If uncertain whether you'll exceed the threshold, register anyway — no penalty for registering when you don't strictly need to, and it avoids scrambling later if income grows.