CIS Registration for Subcontractors: A Plain English Guide for UK Trades

If you work as a subcontractor in construction, one admin task decides how much tax is taken from every payment you receive. It is CIS registration. Register and a contractor deducts 20 per cent from your labour. Stay unregistered and that figure becomes 30 per cent. On £40,000 of labour in a year, the difference is £4,000 sitting with HMRC until you claim it back. This guide explains what CIS registration for subcontractors involves, how to do it, what contractors check, and the mistakes that quietly cost tradespeople money. What the Construction Industry Scheme actually is CIS is HMRC's tax system for construction work. It covers far more than new build sites. Site preparation, demolition, repairs, decorating, plumbing, electrical work, roofing and landscaping all sit inside it. There are two sides to the scheme. Contractors pay subcontractors and must deduct tax from those payments. Subcontractors receive money with tax already taken off. Plenty of trade businesses are both at once: you might be a subcontractor to a main contractor on one job and a contractor to a labourer on the next. The money deducted is not a separate tax. It is a payment on account of the Income Tax or Corporation Tax you will eventually owe. Anything overpaid comes back through your Self Assessment return. Why registering matters The difference between registered and unregistered is ten percentage points on every labour payment. That is real cash flow, and it is cash flow you do not see again until you file. Registration also changes how contractors see you. A main contractor has to verify every subcontractor with HMRC before paying them. If your details do not check out, they must deduct at 30 per cent. Most contractors would rather not carry that friction, so being registered and easy to verify makes you a simpler choice for the next job. How to register for CIS as a subcontractor You need a Unique Taxpayer Reference before you can register. If you already have one from a previous Self Assessment registration, you can register for CIS online through your Government Gateway account. If you do not have a UTR, register as a sole trader for Self Assessment first and select the option confirming that you will work as a construction subcontractor. That single registration covers both. Limited companies register through their business tax account using the company's UTR. Partnerships register in the name of the partnership. Once you are registered, keep your UTR and National Insurance number to hand. You will give both to every contractor you work for, each time you start with a new one. What your contractor does with your details The contractor verifies you with HMRC before the first payment. HMRC tells them which rate to apply: 20 per cent for a registered subcontractor, 30 per cent if you cannot be verified, or nothing at all if you hold gross payment status. After that, the contractor must give you a payment and deduction statement showing what was paid and what was taken off. Keep every one of them. They are your evidence if a deduction is ever queried, and you will need the totals when you file. Getting your invoices right CIS is charged on labour, not on materials. If you buy the bricks, the timber, the fittings or the cable for a specific job, the cost of those materials can be left out of the CIS calculation. That only works if your invoice shows it clearly. Split every invoice into labour and materials, with materials itemised. If a contractor cannot see the split, they may apply the deduction to the whole invoice as a protective measure, and you will spend months chasing the difference. Some costs do not count as materials for CIS purposes. Plant and tool hire, fuel, insurance, general overheads and protective clothing all sit outside the material allowance. Do not bury them in a materials line. Gross payment status and the 0 per cent rate If you want to be paid in full with no deduction at all, apply for gross payment status. HMRC applies three tests. The business test checks that you run a genuine construction business through a business bank account. The turnover test looks at your gross turnover over the last twelve months, excluding VAT and materials: at least £30,000 for a sole trader, or £30,000 per partner or director up to a £100,000 total for partnerships and companies. The compliance test looks at your record of filing and paying tax on time. Approval is not permanent. HMRC reviews gross payment status regularly and can withdraw it if your compliance slips, which usually means a wait of at least a year before you can reapply. What CIS does not do CIS registration does not replace Self Assessment. You still file a return each year declaring all your income, and that return is where your CIS deductions are set against your tax bill. If more has been deducted than you owe, that is where you claim the refund. It also does not cover every payment you receive. Work you do directly for a homeowner is not CIS work, because the homeowner is not a contractor. That income still goes on your return, but nobody deducts tax at source. Common mistakes worth avoiding The most expensive one is treating the deduction as the final tax bill and skipping the return. The second is invoicing labour and materials as a single figure, which invites a 20 per cent deduction on your material costs. The third is letting a contractor pay you without a deduction statement, which leaves you with no paper trail at the end of the year. The fourth is assuming registration is a one-off. If you move from sole trader to limited company, the new entity needs its own registration and its own verification. Getting found by the right contractors Good CIS admin keeps your cash flow straight, but it does not bring you work. Main contractors and homeowners both look for trades they can check quickly: a business name, a location, insurance details, accreditations and reviews in one place. That is what NoaPro is for. A free listing puts your trade business in front of people searching in your area, and a verified badge shows that your details have been checked rather than simply claimed. For a subcontractor chasing steady work, being findable and verifiable is worth as much as a tidy invoice. The short version Register for CIS before you take your first subcontract job. Give every contractor your UTR and National Insurance number, split labour from materials on every invoice, and keep every deduction statement. File your Self Assessment, claim back what you are owed, and apply for gross payment status once your turnover and compliance record support it. If you are building a trade business and want to be found by the right people, list it free at noapro.co.uk.