How to register as self-employed and for CIS

Two different registrations

New subcontractors often get these mixed up. You need both:

1. Self Assessment registration tells HMRC you're self-employed. It gets you a Unique Taxpayer Reference (UTR) and means you'll send a tax return each year.
2. CIS registration tells HMRC you're a subcontractor in construction. It means contractors take 20% off your labour, not 30%.

Registering for CIS doesn't register you for Self Assessment, and the other way round.

Step 1: Register for Self Assessment

You register as a sole trader on GOV.UK. You'll need:

• your National Insurance number;
• your personal details: name, date of birth, address, phone and email;
• the date you started working for yourself;
• the type of work you do and your business address (your home is fine).

You'll be asked to create or sign in to an HMRC online account. When you've registered, HMRC sends your UTR — a 10-digit number — usually by post. Keep it safe: you'll need it for every tax return and for CIS.

The deadline

You must register by 5 October after the end of the tax year in which you started. The tax year runs from 6 April to 5 April.

Don't wait for the deadline if you're working under CIS. You need the UTR to register for CIS, and every week without it can mean 30% deductions.

If you register late, you may have to pay a penalty if you owe tax and pay it late.

Step 2: Register as a CIS subcontractor

Once you have your UTR, register for CIS. You can do it online through your HMRC account or by calling the CIS helpline. You'll need:

• your legal name and any trading name;
• your UTR;
• your National Insurance number;
• your business address.

If you want to apply for gross payment status (no deductions at all), you can do it at the same time, but you'll need to pass the turnover, compliance and business tests. Most new starters won't qualify straight away because of the £30,000 turnover test. See CIS deductions explained.

Step 3: Get verified by each contractor

Before paying you for the first time, a contractor must verify you with HMRC. Give them:

• your name exactly as registered (and trading name if you use one);
• your UTR;
• your National Insurance number.

HMRC tells them which rate to use: 20% if you're registered, 30% if HMRC can't match you, or 0% with gross payment status. If you're suddenly taxed at 30%, check that the contractor has your details exactly right.

Step 4: Set up from day one

A little organisation now saves lots of stress in January.

Keep records

Keep every CIS payment and deduction statement, every invoice, and receipts for your costs. Our guide to CIS records explains what you need and how long to keep it.

Open a separate account

You don't legally need a business bank account as a sole trader, but keeping work money separate makes your records far easier. You'll also need a UK bank account if you ever apply for gross payment status.

Put tax aside

If all your work is under CIS at 20%, you may not need to save much. Work for homeowners and jobs outside CIS have no tax taken at all. Use the tax set-aside calculator to find your figure.

Know your first deadlines

See Self Assessment deadlines and penalties for the full list.

Worked example

Tom finishes his apprenticeship and goes self-employed as a bricklayer on 1 September 2026, working for two local contractors.

• His first tax year is 2026/27 (6 April 2026 to 5 April 2027).
• He must register for Self Assessment by 5 October 2027 — but registers in September 2026 so he has his UTR quickly.
• He registers for CIS once the UTR arrives, so his deductions drop from 30% to 20%.
• He files his first return for 2026/27 by 31 January 2028, and pays any tax then. If CIS has covered most of his bill, he may get money back instead.

Suppose he'd put it off until April 2027 instead. For seven months (September to March), both contractors would have taken 30%. On £2,500 of labour a month, that's an extra £250 a month — £1,750 tied up with HMRC until he files.

If you're also employed

If you have a PAYE job as well as self-employed work, you still register for Self Assessment for the self-employed part. Your job's tax stays as it is, but it uses up some or all of your Personal Allowance, so the tax on your self-employed profit will usually be higher.

Stopping self-employment

If you stop working for yourself, tell HMRC. You'll still need to file a return for the tax year you stopped in, and for any earlier years you haven't filed.