How to Register for CIS as a Contractor or Subcontractor

Zubair Aslam
2 days ago
6 min read

Updated: 2 days ago

Key Takeaways

Subcontractors don't have to register for CIS, but if they don't, contractors must deduct 30% instead of 20% — so registering is almost always worth it.
Contractors must register before making their first payment to a subcontractor; even a single payment triggers the requirement.
You need a Unique Taxpayer Reference (UTR) and a Government Gateway account to register. No UTR yet? Register for Self Assessment first — it can arrive by post in around 10 working days.
Registering online as a new subcontractor via Self Assessment signs you up for Self Assessment and CIS at the same time. Get in touch with a construction-industry specialist accountant, and they can take care of the full process for you.
Contractors must register as an employer with HMRC to operate CIS — even if they have no employees at all.

To register for the Construction Industry Scheme (CIS), you'll need a UTR and a Government Gateway login, then you register online through HMRC. Subcontractors register to have tax deducted at 20% rather than 30%; contractors must register before paying their first subcontractor. If you both do construction work and pay others to do it, you register as both. Here's the full step-by-step for each.

Before you start: what you'll need

Have these ready before you begin, whichever route applies to you:

Your Unique Taxpayer Reference (UTR) — the 10-digit number HMRC issues when you register for Self Assessment (sole traders/partnerships) or Corporation Tax (companies).
A Government Gateway user ID and password — create one if you don't have it; you'll need your National Insurance number and an email address.
Your legal business name (and trading name, if different).
Your National Insurance number (sole traders).
Your VAT registration number, if you're VAT registered.
The date you started trading.
For companies: your Company Registration Number. For partnerships: the registering partner's UTR and NI details.

If you don't have a UTR yet, that's your first job — see Step 1 below.

How to register for CIS as a ***sub*contractor**

Registering as a subcontractor takes you from the 30% deduction rate to 20%. Follow these steps:

Step 1 — Get your UTR (register for Self Assessment if needed)

If you already have a UTR, skip to Step 2. If you don't, register as a new business for Self Assessment on GOV.UK and choose "working as a subcontractor" when prompted — this registers you for Self Assessment and CIS at the same time, saving a step. HMRC posts your UTR out, usually within around 10 working days.

Step 2 — Sign in to Government Gateway

Go to HMRC's CIS registration service and sign in with the Government Gateway user ID and password you used for Self Assessment. If you don't have sign-in details, you can create them during the process.

Step 3 — Register as a subcontractor

Complete the online form with your business details. When asked, choose net payment status (also called "payment under deduction") — this is the standard 20% route that most subcontractors use. If you think you qualify for gross payment status (0%), you can apply for that at the same time, though most subbies starting out choose net.

Step 4 — Submit and get verified

Submit your application. Once you're registered, contractors who verify you with HMRC will be told to deduct 20% instead of 30%. That's it — you're on the scheme.

Prefer not to register online? Sole traders can call the CIS helpline on 0300 200 3210. Partnerships and limited companies that can't register online use HMRC's postal forms instead.

How to register for CIS as a contractor

You're a contractor if you pay subcontractors for construction work — and you must register before you make your first payment. There's no minimum: even one payment triggers the requirement.

Step 1 — Register as an employer with HMRC

This is the step people find surprising: to operate CIS as a contractor, you must first register as an employer with HMRC, even if you have no employees. This sets up the PAYE scheme that CIS runs through. You do it online through GOV.UK or your HMRC business tax account.

Step 2 — Register for CIS as a contractor

As part of setting up as an employer, tell HMRC you'll be a CIS contractor, or add CIS through your business tax account. You'll need your UTR, business details, and (for companies) your Company Registration Number. You can also register by calling the CIS helpline on 0300 200 3210.

Step 3 — Verify subcontractors before you pay them

Once registered, you must verify each subcontractor with HMRC before their first payment. Verification tells you the correct deduction rate — 20%, 30%, or 0% — for that subcontractor.

Step 4 — Meet your monthly CIS duties

As a contractor you must then, each tax month: file a monthly CIS return (CIS300) by the 19th, give each subcontractor a payment and deduction statement within 14 days of the tax month ending, and pay the deductions to HMRC (by the 19th if paying by post, the 22nd electronically).

(Note: a non-construction business that spends more than £3 million on construction over a rolling 12-month period counts as a "deemed contractor" and must register as a contractor too.)

If you're both a contractor and a subcontractor

Plenty of construction businesses are both — you're a subcontractor when you work for a builder, and a contractor the moment you pay a labourer. In that case you register for CIS in both roles and hold both registrations at once. It's common, and entirely normal.

How long does it take, and what happens next?

The online registration itself is quick. The main wait is getting a UTR if you don't already have one, which is around 10 working days by post. Once you're registered, you can check your CIS status through your HMRC business tax account. Contractors should build the monthly return deadline (the 19th) into their routine straight away, as the first £100 penalty applies from day one of lateness.

Common problems and how to fix them

"I've registered but I'm still being deducted 30%." The contractor needs to re-verify you, and your name and UTR must match HMRC's records exactly. A mismatch is the usual culprit.
"I registered for Self Assessment but not CIS." You can add CIS online or by calling the helpline — you don't have to start over.
"I don't have a UTR yet." Register for Self Assessment first and wait for it to arrive before completing CIS registration.
"I'm a contractor with no employees — do I really register as an employer?" Yes. It's simply how HMRC administers CIS; you won't run payroll unless you actually employ someone.

Frequently Asked Questions

Do I have to register for CIS? It depends on your role. Subcontractors don't legally have to register, but unregistered subcontractors have 30% deducted instead of 20%, so most do. Contractors must register — it's mandatory before you make your first payment to a subcontractor for construction work.

Do I need a UTR to register for CIS? Yes. Your UTR is essential for CIS registration. If you don't have one, register for Self Assessment first (or Corporation Tax if you're a company), and HMRC will issue your UTR — usually by post within about 10 working days — which you then use to complete CIS registration.

Can I register for CIS by phone? Yes. Sole traders can register by calling the CIS helpline on 0300 200 3210. Partnerships and limited companies that can't use the online service register by post instead. Online is usually the quickest route if you already have your UTR and Government Gateway login.

Do contractors really have to register as an employer even with no employees? Yes. Registering as an employer sets up the PAYE scheme that CIS operates through, so it's a required step for contractors regardless of whether you employ anyone. You won't have to run payroll unless you take on actual employees. This trips a lot of new contractors up, so it's worth getting set up correctly from the start.

Can I be registered as both a contractor and a subcontractor? Yes, and many construction businesses are. You register in both roles and hold both registrations simultaneously — as a subcontractor for the work you're paid to do, and as a contractor for the subcontractors you pay.

Get set up today

Talk to the SiteLedger team on 0161 513 0027 and we'll handle your CIS registration, subcontractor verification, and monthly returns for you. As construction-specialist accountants, this is all we do — so it's one less headache for you.

Written by the SiteLedger team — construction-specialist accountants. Last reviewed: July 2026. Process and figures apply to the 2026/27 UK tax year. This is general guidance, not personal tax advice; your position depends on your circumstances, so speak to us about your specific business.