Yes, if you work as a construction subcontractor, you should register with the Construction Industry Scheme. Registering brings your deduction rate down to 20% instead of the 30% charged to unregistered subcontractors, and gross payment status can bring it to 0%.
To start, you will need:
- Your Unique Taxpayer Reference (UTR)
- Your National Insurance number (sole traders) or company registration number (limited companies)
- Your legal business name and the date you started trading
Your immediate next step is to sign into your HMRC online account to register for CIS, or gather these details ready to complete form CIS302 if you are a sole trader without online access.
Key Takeaways
| Point | Details |
|---|---|
| Register before your first invoice | Unregistered subcontractors are taxed at 30% rather than 20%, so register before accepting work. |
| Match your details exactly | UTR, National Insurance number and CRN must match HMRC’s records or verification fails. |
| Separate labour from materials | Only labour is subject to CIS deductions, so itemise invoices to protect your cash flow. |
| Gross status needs a clean history | HMRC expects roughly a year of compliant filing and turnover evidence before approving 0% deductions. |
| Get professional support if unsure | CWABC offers CIS registration, payroll and return support for subcontractors across Kent and the UK. |
Need help?
If you’d rather have someone sort your CIS registration, verification and returns properly, get in touch with CWABC and I’ll take it from there.
Table of Contents
- Who counts as a CIS subcontractor or contractor?
- How to register as a subcontractor step by step
- How does verification affect your deduction rate?
- Gross payment status: is it worth applying for?
- Invoicing correctly and claiming your CIS deductions
- What goes wrong, and how to fix it
- How I can help with CIS registration and returns
- A quick checklist I run through with subcontractor clients
- Get your CIS registration and returns handled properly
- Sources
Who counts as a CIS subcontractor or contractor?
Under CIS, a subcontractor is anyone paid to carry out construction work for a contractor, whether that’s groundworks, plastering, electrical work or site clearance. A contractor is any business that pays subcontractors for construction work, including some businesses outside construction, such as large retailers or councils, who spend heavily enough on building work to become “deemed contractors.”
CIS is a tax withholding scheme, not a test of employment status. Registering as a CIS subcontractor doesn’t automatically mean you’re self-employed for tax purposes generally, and it certainly doesn’t settle whether you’re employed or self-employed for other legal purposes. HMRC’s own internal guidance on subcontractor verification is clear that separate status checks apply. If there’s genuine doubt, the Check Employment Status for Tax (CEST) tool, or advice from an accountant, is the right route, not your CIS registration status.
How CIS applies depends on your structure:
- Sole traders: register personally using your UTR and National Insurance number.
- Partnerships: each partner registers individually, plus the partnership itself.
- Limited companies: register using the company’s UTR and Companies House registration number (CRN).
How to register as a subcontractor step by step
Registration differs slightly depending on how your business is set up, but the documents you need overlap considerably.
- Get your UTR first. If you don’t have one, you’ll need to register for Self Assessment before you can register for CIS. HMRC typically issues a UTR within about ten working days by post, longer if you’re registering from overseas.
- Gather your identifiers. Sole traders need their UTR and National Insurance number. Limited companies need their company UTR and CRN. Partnerships need the UTR for each partner and for the partnership itself.
- Register online. Sign into your HMRC online account and add CIS as an activity if you already have a Government Gateway login. This is the fastest route for most people.
- Use the paper forms if needed. Sole traders without online access use form CIS302; partnerships use CIS304. HMRC processes postal applications, but expect it to take noticeably longer than the online route.
- Prepare supporting evidence. Have your business bank details, trading start date and business name ready, since HMRC will ask for all of these during registration.
According to HMRC’s guidance for CIS subcontractors, the legal business name, UTR and start date are non-negotiable requirements regardless of structure.
Pro Tip: Register before you accept your first contract, not after. Contractors are legally required to verify you before paying you, and a subcontractor who isn’t yet in HMRC’s system gets the 30% rate by default, even if you’re mid-registration.
How does verification affect your deduction rate?
Before a contractor pays you for the first time (unless they’ve included you on a return within the last two tax years), they must verify you with HMRC. The verification process checks your UTR, legal business name and, for limited companies, your CRN against HMRC’s records.
Three outcomes follow:
- Verified, standard rate: 20% deducted from your labour payments. This is the outcome for most registered subcontractors.
- Verified, gross payment status: 0% deducted. HMRC has confirmed you meet the gross status tests.
- Not matched or not registered: 30% deducted. This happens when details don’t match HMRC’s records, or you haven’t registered at all.
Accuracy matters enormously here. HMRC’s internal manual on verification sets out precisely what a contractor must supply when verifying you and makes clear that contractors carry liability if they get verification wrong. That’s exactly why contractors tend to be fussy about getting your UTR and NINO exactly right before the first invoice, not through bureaucratic nit-picking, but because HMRC internal guidance puts the risk on them if they don’t.
Gross payment status: is it worth applying for?
Gross payment status means contractors pay you in full, with no CIS deduction at all, leaving you to settle your tax bill through Self Assessment or Corporation Tax. HMRC applies three broad tests before granting it:
- Business test: you must be running a genuine construction business in the UK.
- Turnover test: your construction turnover must clear HMRC’s threshold, excluding VAT and materials.
- Compliance test: your tax returns and payments need a clean recent history, with no significant late filings or missed payments.
To apply, sole traders and partnerships generally use forms CIS302 and CIS304 respectively, while limited companies apply through their CIS registration online. Many applications fail simply because the applicant hasn’t yet built twelve months of clean filing and turnover evidence, so it pays to have a year of reconciled bank statements and invoices ready before you apply.
Gross status isn’t permanent. HMRC reviews it regularly and can withdraw it if your compliance slips, so keeping returns and payments on time matters just as much after approval as before it.
Invoicing correctly and claiming your CIS deductions
Only the labour element of your invoice is subject to CIS deductions. Materials, plant hire and consumables should be listed separately and paid in full, a distinction the Low Incomes Tax Reform Group’s CIS guidance sets out clearly.
- Split your invoice into labour, materials and plant hire, with VAT shown separately if you’re registered.
- Keep every deduction statement the contractor issues you, since these show the CIS deducted and form your evidence when reclaiming tax.
- Record deductions correctly. Sole traders enter CIS deductions on the Self Assessment CIS section; limited companies offset deductions against PAYE and Corporation Tax liabilities through payroll records.
In your bookkeeping software, whether Xero, QuickBooks or FreeAgent, set up a dedicated “CIS deductions suffered” ledger code so the figure is always ready at year-end. My detailed CIS guide for subcontractors covers invoice templates in more depth.
Pro Tip: An invoice that lumps labour and materials together as one figure risks CIS being deducted from the whole amount, materials included. Itemise it properly and you keep that cash in your account instead of waiting months to claim it back.
What goes wrong, and how to fix it
Skipping registration costs you the 30% rate rather than 20%, and vague invoices risk overpaying CIS on materials that should never have been deducted from.
- Verification fails or details don’t match: check your UTR, legal name and NINO/CRN against your HMRC record, then ask the contractor to re-verify.
- Contractor deducts the wrong amount: request a corrected deduction statement immediately, in writing.
- Dispute persists: contact HMRC’s CIS helpline directly, or get an accountant involved before it affects your Self Assessment.
How I can help with CIS registration and returns
As an AAT-licensed bookkeeper, I help subcontractors across Kent and remotely UK-wide with CIS. My services include:
- Registration support for sole traders, partnerships and limited companies
- Payroll and CIS return filing
- Invoice templates that separate labour and materials correctly
- Cloud software setup in Xero, QuickBooks or FreeAgent
Everything runs paperless, with pricing agreed upfront. Get in touch if you’d like help getting registered properly.
A quick checklist I run through with subcontractor clients
Before any first payment, I check the basics: UTR, National Insurance number or CRN all correct and matching HMRC’s records; invoices itemising labour, materials and plant hire separately; verification confirmed before work starts. When something’s wrong, the fix is usually simple, reissue the invoice with labour broken out, or correct a mismatched digit in the UTR.
— Chris
Get your CIS registration and returns handled properly
There’s more than one way to sort CIS: you can wade through HMRC’s online portal yourself, or hand the whole thing to a payroll bureau that treats you as one file among hundreds. CWABC offers a third option, direct, personal support from an AAT-licensed bookkeeper who actually understands construction invoicing and knows why itemising labour and materials protects your cash flow.
My Payroll & CIS support in Tonbridge covers registration, monthly CIS returns, deduction statement checks and payroll, all run through cloud software like Xero or QuickBooks with pricing agreed before any work starts. If you’re weighing up mortgage or lending paperwork alongside your CIS status, this guide to documentation for subcontractors is worth a look too. If your invoices, registration or deductions need sorting properly, get in touch to discuss your CIS support and I’ll talk you through what needs doing first.
