Registering as a CIS Contractor

Key facts

You must register as a CIS contractor before paying any subcontractor for construction work.
Registration can be done online via your HMRC business tax account, or by phone on 0300 200 3210.
You will need your Unique Taxpayer Reference (UTR) and, for companies, your company registration number.
Once registered, you must verify subcontractors, make deductions, file monthly returns, and pay HMRC.
Failure to register can result in penalties and the inability to reclaim CIS deductions as business expenses.

Who Must Register as a CIS Contractor?

You must register with HMRC as a CIS contractor if you pay subcontractors for construction operations. This applies whether you are:^[1]

A sole trader who subcontracts work to other tradespeople
A partnership that hires subcontractors for construction projects
A limited company paying subcontractors for construction work
A deemed contractor (non-construction business spending over £3 million on construction)
A government body or local authority commissioning construction

You must register before making your first payment to any subcontractor. Making payments without being registered is a compliance failure that can attract penalties.

No minimum threshold: There is no minimum payment level or minimum number of subcontractors. Even if you hire just one subcontractor for a single small job, you must be registered as a CIS contractor before paying them.

How to Register

You can register as a CIS contractor through two channels:^[2]

Online Registration

Sign in to your HMRC business tax account (Government Gateway)
Navigate to the Construction Industry Scheme section
Select “Register as a contractor”
Enter your business details, UTR, and (for companies) company registration number
Confirm your registration

Phone Registration

Call the CIS helpline on 0300 200 3210 (Monday to Friday, 8am to 6pm). Have the following information ready:

Your Unique Taxpayer Reference (UTR)
Your National Insurance number (sole traders/individuals)
Your company registration number (limited companies)
Your business name and address
The date you expect to make your first subcontractor payment

What You Need Before Registering

Business Type	Required Information
Sole trader	UTR, National Insurance number, name, address, date of birth
Partnership	Partnership UTR, partner details, partnership name and address
Limited company	Company UTR, company registration number, registered office address, director details

Tip: If you do not yet have a UTR, you will need to register for Self Assessment (sole traders/partnerships) or Corporation Tax (companies) first. HMRC will issue a UTR, which you then use to register for CIS. Allow at least 10 working days for your UTR to arrive.

What Happens After Registration

Once registered as a CIS contractor, you must:^[1]

Verify every subcontractor with HMRC before making the first payment under each contract
Make CIS deductions from payments at the rate HMRC specifies (0%, 20%, or 30%)
Give the subcontractor a written payment and deduction statement within 14 days of the end of each tax month
File a monthly CIS return (form CIS300) with HMRC by the 19th of each month
Pay total deductions to HMRC by the 19th (post) or 22nd (electronic) of each month
Keep records for at least 3 years after the end of the tax year

CIS and PAYE Employer Status

Registering as a CIS contractor is separate from registering as a PAYE employer. If you have employees as well as subcontractors, you need both registrations.^[1]

CIS deductions are paid alongside your PAYE liabilities but reported on separate CIS returns (not on your RTI submissions). The payment reference for CIS is typically the same as your PAYE Accounts Office Reference.

Changing Your Registration Details

If your business details change (e.g. address, business name, or business structure), you must notify HMRC. You can update most details online through your business tax account or by contacting the CIS helpline.

If your business structure changes significantly — for example, if you incorporate from sole trader to limited company — you will need to cancel the old CIS registration and register under the new entity.

De-Registering as a CIS Contractor

If you stop using subcontractors permanently, you can de-register as a CIS contractor by contacting HMRC. Before doing so:

File all outstanding CIS returns (including nil returns for months with no payments)
Pay all outstanding CIS deductions to HMRC
Keep your records for the required retention period (3 years)

Frequently Asked Questions

When must I register as a CIS contractor?

You must register as a CIS contractor before you make your first payment to a subcontractor for construction work. There is no minimum payment amount or number of subcontractors — even one payment triggers the registration requirement.

How do I register for CIS as a contractor?

You can register online through your HMRC business tax account (Government Gateway), or by phoning the CIS helpline on 0300 200 3210. You will need your UTR, business details, and for companies, your company registration number.

What if I am already registered as a subcontractor?

If you are already registered as a CIS subcontractor and now need to take on your own subcontractors, you must also register as a contractor. You can hold both registrations simultaneously.

Can I register as both a contractor and subcontractor?

Yes. Many construction businesses need both registrations. You register separately for each role, and you must fulfil the obligations of both — making deductions from your subcontractors while having deductions taken from your own payments.

Sources

What you must do as a CIS contractor — GOV.UK
Register as a CIS contractor — GOV.UK
Construction Industry Scheme (CIS) — GOV.UK