How does the Construction Industry Scheme (CIS) deduction work for subcontractors?

Full answer

The Construction Industry Scheme is a sector-specific withholding tax system designed to reduce tax evasion in construction, and both contractors and subcontractors need to understand their respective obligations to stay compliant. **Who CIS applies to** CIS applies to most construction work in the UK, covering not just main building contractors but also many businesses spending significant amounts on construction operations as part of their wider business (deemed contractors). "Subcontractors" under CIS can be self-employed individuals, partnerships, or limited companies carrying out construction work for a contractor. **The three deduction rates** A contractor must deduct tax from a subcontractor's payment at one of three rates: 0% for subcontractors who have applied for and been granted "gross payment status" (meaning no deduction at all, with the subcontractor responsible for paying their own tax through normal Self Assessment/Corporation Tax); 20% for subcontractors registered under CIS but without gross payment status; or 30% for subcontractors who are not registered under CIS at all -- registering, even without qualifying for gross status, is clearly worthwhile to avoid the higher 30% deduction rate. **What the deduction is calculated on** Crucially, the CIS deduction is calculated on the labour element of the payment only -- materials, VAT, and certain other specified costs (such as equipment hire that is separately itemised) should be excluded from the amount the deduction percentage is applied to, provided the subcontractor's invoice clearly separates out these costs; if materials costs are not clearly itemised, HMRC may expect the deduction to be applied to the full gross payment. **Verification process** Before paying a new subcontractor, a contractor must "verify" them with HMRC (checking their CIS registration status and the correct deduction rate to apply) using their Unique Taxpayer Reference and other identifying details -- this determines which of the three rates applies to that specific subcontractor. **Reclaiming CIS deductions** Because CIS deductions are calculated on gross payments before the subcontractor's actual allowable business expenses and profit margin are taken into account, the amount deducted often significantly exceeds the subcontractor's real tax liability once their Self Assessment return is completed -- overpaid CIS deductions are reclaimed either as a reduction against the subcontractor's overall Self Assessment tax bill, or, for a limited company subcontractor, offset against their PAYE/Corporation Tax liabilities, with any remaining excess refundable. **Gross payment status** Subcontractors can apply for gross payment status if they meet specific tests around their business's turnover, a good compliance history (filing and paying taxes on time), and having appropriate business bank account arrangements -- gaining gross status significantly improves cash flow, since payments are received in full without any CIS deduction at source, though the subcontractor must then manage their own tax payments proactively through Self Assessment. **Worked example** A registered (but not gross-status) self-employed bricklayer invoices a contractor £3,000 for a job, itemising £2,000 for labour and £1,000 for materials. The contractor applies the 20% CIS deduction only to the £2,000 labour element (£400), paying the bricklayer £2,600 net (£1,000 materials plus £1,600 net labour) and remitting the £400 deducted to HMRC on the bricklayer's behalf. At the end of the tax year, when the bricklayer completes his Self Assessment return and calculates his actual tax liability after allowable expenses, he can offset the total CIS deductions withheld throughout the year against his final tax bill, with any excess refunded. **Practical tip** Subcontractors should keep clear records of all CIS deductions withheld throughout the year (contractors must provide monthly CIS payment/deduction statements) to ensure the correct total is claimed back on the Self Assessment return, since HMRC will not automatically identify or apply an overpayment without this being properly reported.

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