How to Register as Self-Employed with HMRC UK — A Tradesperson's Guide (2026)

If you've just gone out on your own — or you've been picking up cash jobs for a while and are starting to take it more seriously — registering as self-employed with HMRC is one of the first things you need to get done. It's not complicated, but the rules around who must register, when, and what happens if you miss the deadline are worth understanding clearly. This guide walks through the whole process.

Who needs to register as self-employed

If you earn more than £1,000 from self-employment in a tax year, you must register as self-employed with HMRC and file a Self Assessment tax return. The £1,000 figure is called the trading allowance. It applies to your gross income (what you charge clients), not your profit after expenses.

This applies whether you're a plumber, electrician, builder, painter, groundworker, or any other tradesperson working for themselves. It doesn't matter whether you also have a PAYE job alongside your self-employed work — if self-employed earnings exceed £1,000, registration is required.

Registering makes you a sole trader in HMRC's eyes. You trade as yourself — you don't need to register at Companies House or form a limited company. It's the simplest business structure available and the one most tradespeople starting out use.

The deadline for registering

You must register by 5 October in the second tax year of trading. The UK tax year runs from 6 April to 5 April.

So if you started earning self-employed income during the 2025–26 tax year (any time between 6 April 2025 and 5 April 2026), you must register by 5 October 2026. If you started in 2024–25, your deadline was 5 October 2025.

Don't wait until the deadline. Registering early gives HMRC time to set up your records, issue your Unique Taxpayer Reference, and get you enrolled for Self Assessment before your first filing deadline arrives. Leaving it late is an easy way to end up filing in a rush or missing a deadline you weren't expecting.

Missing the 5 October deadline can result in a penalty — even if you owe no tax. HMRC takes registration seriously because it's the mechanism that gets you into the system.

What you'll need to register

The registration process is straightforward. Before you start, have the following to hand:

• National Insurance number — your NI number is the most important piece of information. It ties your registration to your identity in HMRC's systems
• Personal details — name, date of birth, home address, phone number, email address
• Business details — the nature of your trade (e.g. plumber, electrician, general builder), your trading name if you have one (e.g. “JD Plumbing Services” — though trading as your own name is also fine), your business start date, and your business address
• Business address — for most sole traders, your home address is fine. You don't need a separate commercial address

You'll also need access to an email address to set up or log in to your Government Gateway account.

How to register: step by step

Registration is done online at gov.uk. The form you're completing is called the CWF1, though you don't need to find it by name — just search “register for Self Assessment” on gov.uk and follow the links. The whole process takes around 10 minutes.

• Step 1 — Go to gov.uk and search “Register for Self Assessment”. Select the option for self-employment (as opposed to other income types like property)
• Step 2 — Sign in to your Government Gateway account. If you don't have one, create one — you'll need your NI number and email address. You'll set a password and may be asked to verify your identity
• Step 3 — Complete the CWF1 form. You'll be asked for your personal details, your business start date, the nature of your trade, and your contact information
• Step 4 — Submit the form. You'll receive a confirmation on screen and by email

That's it. HMRC does the rest from here.

What happens after you register

Within 10 working days of registering, HMRC will send a letter to your home address containing your Unique Taxpayer Reference (UTR). Your UTR is a 10-digit number that identifies you with HMRC for tax purposes. You'll use it every time you file a return or correspond with HMRC. Keep it safe — treat it like a password.

HMRC will also enrol you for Self Assessment and send you an activation code for your online HMRC account (if you haven't already got access). Once activated, you can view your tax position, file returns, make payments, and correspond with HMRC entirely online.

Your first Self Assessment tax return will cover the tax year in which you started self-employment. The online filing deadline is 31 January following the end of that tax year — and any tax owed is due on the same date.

If you work in construction: register for CIS too

If you work in construction and will be taking on work from contractors — or will be using subcontractors yourself — you also need to register for the Construction Industry Scheme (CIS).

As a CIS subcontractor, contractors are required to deduct tax from your payments before they pay you and send it directly to HMRC on your behalf. If you register for CIS, that deduction rate is 20%. If you don't register, contractors must deduct at the higher rate of 30%. That extra 10% will sit with HMRC until you reclaim it through your Self Assessment return — meaning you're effectively giving HMRC an interest-free loan.

You register as a CIS subcontractor through the same HMRC online portal, using your Government Gateway account. You can do it at the same time as your self-employment registration or separately. If you achieve Gross Payment Status (by meeting income and compliance thresholds), contractors can pay you in full without any CIS deduction at all — worth aiming for once you're established.

Open a business bank account

As a sole trader, you're not legally required to have a separate business bank account. But it's strongly recommended. Keeping your business and personal finances in separate accounts makes bookkeeping significantly easier, speeds up your year-end tax filing, and makes it straightforward to demonstrate your income and expenses if HMRC ever opens an enquiry.

Several challenger banks offer free or low-cost business accounts that are well-suited to sole traders: Starling Business, Monzo Business, and Tide are popular options. High-street banks also offer business accounts, though many charge monthly fees. Opening one takes around 15 minutes online.

Do you need to register as a company too?

No. Registering as self-employed with HMRC makes you a sole trader — you trade as yourself. You do not need to register at Companies House, and you do not need to form a limited company.

Operating as a sole trader is simpler and has lower admin overhead than running a limited company. For most tradespeople starting out, it's the right structure. If your income grows significantly and you want to reduce your personal tax liability, forming a limited company becomes worth exploring — but that's a separate decision for later, not something to worry about when you're just getting started.

What tax you'll owe as a sole trader

As a self-employed sole trader, you pay two types of tax on your profits: Income Tax and Class 4 National Insurance. You pay no tax on your first £12,570 of profit — that's the personal allowance for 2024–25.

• Profit up to £12,570 — 0% Income Tax, 0% Class 4 NI
• Profit £12,571 to £50,270 — 20% Income Tax and 6% Class 4 NI
• Profit above £50,270 — 40% Income Tax and 2% Class 4 NI

A practical rule of thumb: set aside 25–30% of your net profit for tax. If your profit sits in the basic rate band, your combined Income Tax and Class 4 NI liability will be around 26%. Having that money in a separate savings pot means you're never scrambling when the January bill arrives.

What to do immediately after registering

Once you've registered and received your UTR, there are a few practical steps to take straight away:

• Open a business bank account and route all income and business spending through it from day one
• Set up basic bookkeeping — at minimum a spreadsheet logging income and expenses with dates. Accounting software (Xero, QuickBooks, FreeAgent, or Trade2Base) automates most of this
• Keep every receipt — materials, tools, fuel, insurance, workwear. Photograph them on the day and store digitally
• Set aside money for tax as you go — don't wait until January. Each time you get paid, move a portion to savings
• Note your filing deadline — your first Self Assessment return is due by 31 January following the end of your first full tax year. Mark it in your calendar now

Common mistakes to avoid

A few errors come up repeatedly among tradespeople registering for the first time — all of them avoidable:

• Not registering at all — HMRC has access to data from banks, payment processors, job platforms and other sources. They do catch up with unregistered self-employed earners, and the consequences include back-taxes, penalties and interest
• Registering too late — missing the 5 October deadline triggers an automatic penalty even if you owe no tax. Don't confuse the 5 October registration deadline with the 31 January filing deadline — they're different things
• Not setting aside money for the tax bill — spending everything you earn in year one and then receiving a tax bill in January is one of the most common financial shocks new tradespeople face. It's entirely preventable
• Not keeping receipts — without receipts you can't claim expenses, and you'll pay more tax than you owe. Keep everything from the day you start trading
• Ignoring CIS registration if you work in construction — the 10% difference between the standard and unregistered deduction rate adds up to real money quickly