How do I Register for CIS as a Subcontractor?

The Construction Industry Scheme (CIS) should be used by subcontractors who do construction work for a contractor.

CIS registration is not mandatory for subcontractors. However, without CIS registration, contractors will take 30% tax from your gross earnings.

If you opt for voluntary CIS registration, your tax deduction is reduced to 20%.

The CIS process is not for people working in the construction industry as an employee under PAYE.

It is only for individuals who are taken on by construction industry contractors as a subcontractor and are considered self employed.

If you are a construction worker and you want to register for CIS, there are a few simple steps to follow.

All CIS registration is online and there are some differences in the process, depending on how your work situation is defined.

It’s important to note that registering under CIS is a separate requirement from self-employed registration for self assessment. You must complete both registrations independently.

Checklist for CIS registration

Before you start, no matter what your status, you will need to have specific information to complete the CIS registration procedure.

You need the following things at your fingertips:

• Your National Insurance Number.
• Your business’s Unique Taxpayer Reference (UTR) number.
• Your legal or trading business name.
• If you’re VAT registered, you also need your VAT registration number.

CIS scheme registration next steps

This depends on your current status.

• Self employed: If you are already registered as self employed, the process of CIS registration will only take a few days to complete because you already have a UTR and can do it online. You need your Government Gateway username and password.
• If you are not already registered as self employed, you can do this and register for CIS at the same time.

You need to make sure to choose ‘working as a subcontractor’ as you complete your self assessment registration form.

This way of CIS registration, understandably takes longer to be fully registered and you will be given a CIS card at the end of the process.

• Limited Company or Partnership: If you are classified as a limited company or partnership, then you register for CIS through their different respective processes. You will need your UTR and business trading name details to complete these registration forms.
• Based outside the UK: The CIS applies to all subcontracted work done in the UK, so you are still able to join the CIS if you are based abroad. There are different forms and procedures depending on what type of business you have.
• Subcontractor and contractor: If you are both a subcontractor and contractor, you must register both your positions on the construction industry scheme as separate entities.

Do I get a CIS number after I have registered?

Under the construction industry scheme HMRC uses your self assessment unique taxpayer reference (UTR) as your primary identification number.

It’s important to note that there isn’t a distinct identification number called a “CIS number.”

When contractors or other construction professionals mention your CIS number, they are usually referring to your self assessment UTR number.

A UTR is made up of 10-digits and is automatically assigned by HMRC when your self assessment registration is completed.

Your UTR:

• Acts as your official identifier within the CIS framework.
• Enables HMRC to monitor your earnings and associated tax deductions.
• Creates a direct link to your self assessment tax records.
• Helps verify your status as a registered CIS contractor or subcontractor.
• Ensures accurate processing of payments and deductions within the scheme.

Do I need to complete a CIS tax return?

As a CIS sub contractor a self assessment tax return will have to be completed after the end of each tax year.

A tax return must be completed to declare your self employed income and tax figures along with any other income you may have (for example from a job where you are employed under PAYE).

Depending on your income levels and the amount of overall income tax paid deducted you could be owed a tax refund.

Most subcontractors in the construction industry will be affected by making tax digital which will mean changes to the way you report your pay and tax information to HMRC.

I’m new to CIS – what paperwork do I actually need for my refund?

Starting your first CIS tax refund claim can feel overwhelming, but the documentation requirements are straightforward once you understand them.

You’ll need proof of all money earned (CIS statements, payslips, P45/P60 forms) and evidence of business expenses (receipts, bank statements, mileage records).

Think of it as telling HMRC the complete story of your working year – every pound earned and every legitimate business cost incurred.

Missing documentation can delay your refund or reduce the amount you’re entitled to claim back.

How do I track all my CIS documentation?

Managing documentation from contractors requires a systematic approach to ensure nothing gets overlooked.

Create a simple filing system with separate folders for each contractor, containing their CIS statements and payment records.

Many successful subcontractors use a monthly checklist to verify they’ve received all expected documentation.

Set up a spreadsheet tracking payments from each contractor, making it easier to spot missing statements.

Remember, each contractor should provide monthly CIS statements – if you haven’t received one, contact them promptly as you’ll need these for your refund claim.

Do I have to register for CIS annually?

No, you just register for CIS once. As and when your circumstances change, you are obliged to inform HMRC and they will make any necessary changes to your tax status.

What kind of work is eligible under CIS rules?

The CIS rules apply to most trades in the construction industry, including; plumbers, electricians, builders, groundworkers and joiners. From razing a building to the ground, to the final coat of paint, the CIS is mandatory for most contractors.

Is the CIS scheme only for UK based companies?

No, the CIS is not restricted to British companies. Businesses from abroad can register as CIS contractors, with some slight differences to the application process, as long as the construction work itself is being done in the UK.

How to get help with registering for the CIS as a subcontractor

HMRC has a dedicated helpline for CIS registration, 0300 200 3210. They can talk you through the process and make sure that you are registering in the correct way for your business type.