If you work in construction under your own name or through your own company, CIS is usually one of the first things to sort out. If you do not register, contractors deduct 30% instead of 20%, which makes a real dent in every payment. The registration itself is simple and takes about 20 minutes online.
Do you need to register for CIS?
You need to register if you do construction work for a contractor and are paid as a business, not as an employee. That covers sole traders, partnerships, and limited companies. If you work through an umbrella company on PAYE, you do not register for CIS.
You can still do the work without registering, but the deduction rate changes. Unregistered subcontractors are deducted at 30%, not 20%. Over a year, that ties up cash until it is sorted out through self-assessment, even though you usually get it back later.
If you are thinking about umbrella PAYE instead of self-employment, CIS registration does not apply to you. An umbrella company puts you on PAYE, so CIS deductions do not apply to employees.
See who CIS applies to for the full explanation.
What do you need before registering?
Before you register as a CIS subcontractor, make sure you have:
– A Unique Taxpayer Reference (UTR). Every self-employed person and limited company has one. If you have not registered for self-assessment yet, do that first. HMRC sends your UTR by post within about 10 working days.
– A Government Gateway account. This is your HMRC online portal. You need a Government Gateway user ID to register for CIS and manage everything afterwards.
– National Insurance number. Sole traders need this. Your NI number appears on your payslip from any previous employment.
– Legal business name and address. For sole traders, that means your name and address. For companies, it means the registered company name and Companies House registration number.
For limited companies, HMRC may also ask for all directors’ UTRs during the process, especially if you later apply for GPS.
Step-by-step: how to register online
Step 1: Log in to your HMRC Government Gateway account at gov.uk. If you do not have one, create it first. You will verify your identity with a photo ID or existing HMRC credentials.
Step 2: Go to CIS. In the Government Gateway dashboard, look for “Construction Industry Scheme (CIS)” under your taxes. Select “Register as a subcontractor.”
Step 3: Enter your details. You will need your UTR, NI number, legal name, and the type of construction work you do. HMRC uses this to classify your activity correctly.
Step 4: Submit. HMRC usually processes the registration within a few working days. You will get confirmation.
Step 5: Tell the contractors who pay you. After you are registered, they need to verify your status before the first payment. They do this through HMRC’s verification system. HMRC confirms your registration and tells them your rate, which is 20% for standard deductions.
You do not need to do anything else. The contractor handles verification on their side.
What happens after registration?
Once you are registered, contractors who verify you will be told to use the 20% rate. Any payments you received before registration at 30% can be corrected at year end through self-assessment.
Keep a note of the date you registered. Any payments made before that date at 30% still count as CIS deductions suffered, so they can be set against your tax bill on self-assessment.
HMRC keeps your registration active as long as you stay compliant. You do not need to renew it every year. You do still need to file your self-assessment return and stay on top of your tax affairs.
What are the deduction rates once you’re registered?
Registered subcontractors are deducted at 20% on the labour part of their payments. Unregistered subcontractors are deducted at 30%. GPS holders receive payments with no deduction.
See CIS deduction rates for the full detail, including how materials exclusions work and how deductions are credited against your annual tax.
Do you also need to register as a contractor?
Only if you pay other subcontractors yourself. Registering as a subcontractor and registering as a contractor are separate steps. If you take on subcontractors of your own, you also need to register as a CIS contractor with HMRC and file monthly returns.
Many construction businesses are both. They get paid as a subcontractor and pay others as a contractor. If that applies to you, you need both registrations.
Can you register by phone?
Yes. HMRC’s CIS helpline can take subcontractor registrations. Call the helpline with your UTR, NI number, and business details ready. Online registration is still faster and gives you an immediate confirmation record.
The CIS helpline number is on gov.uk under “Construction Industry Scheme.” Call during HMRC’s published opening hours.
