What CIS compliance means in practice (and who needs to follow it)
CIS compliance is the day-to-day process of operating the Construction Industry Scheme correctly: checking who you’re paying, applying the right deductions, reporting those payments to HMRC on time, and keeping clear records. In practice, a simple UK CIS compliance checklist for contractors usually covers:
- Registering for CIS if you pay subcontractors for construction work (including labour-only and mixed labour/material invoices).
- Verifying each subcontractor with HMRC before first payment to confirm whether they’re paid gross or at 20%/30% deduction rates.
- Calculating deductions correctly: apply CIS only to the labour element (and certain charges like hire with operator), not to materials (and usually not to VAT). If the invoice isn’t split, you may need a reasonable breakdown.
- Issuing payment and deduction statements to subcontractors each time you pay them, showing how the deduction was worked out.
- Submitting monthly CIS returns to HMRC and making the required declarations (including that subcontractors are not treated as employees where appropriate).
- Paying HMRC on time for CIS deductions and keeping supporting records (invoices, verification numbers, statements, and proof of materials).
Who needs to follow CIS? Mainly contractors who pay subcontractors for construction operations in the UK. This includes building firms and also “deemed contractors” (non-construction businesses that spend heavily on construction). Subcontractors also have responsibilities: give correct details for verification, check statements, and account for CIS deducted when completing their tax return.
Repeatable CIS process: step-by-step checklist from onboarding to monthly return
- Onboard the subcontractor (before any labour starts)
- Collect full name, trading name, UTR, NI number (if sole trader), company number (if limited), and contact details.
- Get written confirmation of VAT status and whether they’ll invoice through a limited company or as an individual.
- Agree what counts as labour vs materials on invoices (CIS applies to labour; materials are usually excluded from the deduction).
- Verify with HMRC (each new subcontractor)
- Verify the subcontractor in your CIS online account/software to confirm the correct deduction rate (0%, 20%, or 30%).
- Save the verification reference and date in your job folder.
- Set up job and payment controls (once per job)
- Create a standard invoice template request: labour, materials, VAT (if applicable), and any plant hire shown separately.
- Decide your internal approval steps: site sign-off, invoice check, then payment run.
- Process each invoice (every payment)
- Check the invoice matches the job and splits labour/materials clearly.
- Calculate CIS deduction on the labour element (excluding materials) at the verified rate.
- Issue a CIS payment/deduction statement to the subcontractor for each payment.
- Submit the monthly CIS return (every month)
- Reconcile payments made to subcontractors and confirm deduction totals.
- File the CIS return for the tax month and make the required declaration.
- Pay HMRC by the deadline and archive all invoices, statements, and verification records.
CIS options compared: gross vs net status, PAYE vs CIS, in-house vs accountant vs software
Choosing the right CIS setup affects cashflow, admin time, and how quickly you can prove compliance if you’re queried. Use the comparisons below to decide what fits your contracting business.
- Gross vs net status (CIS): With net status, contractors deduct CIS tax at source (usually 20% for verified subcontractors, 30% if not verified) and pay you the remainder. With gross payment status, you’re paid in full and handle tax through your own returns. Gross status can help cashflow, but you must keep records tight and meet HMRC compliance tests to keep it.
- PAYE vs CIS: PAYE is for employees and includes income tax and National Insurance through payroll; it generally involves employment rights and employer duties. CIS is for subcontractors in construction services, where deductions are withheld by the contractor and reported monthly. If someone’s working like an employee, PAYE may be more appropriate than CIS, so document working arrangements and check status regularly.
- In-house vs accountant vs software: In-house works if you have a consistent process for verifying subcontractors, collecting UTRs, issuing payment/deduction statements, and filing monthly returns on time. An accountant can reduce risk and handle edge cases (mixed labour/material invoices, retentions, corrections). Software can automate verification prompts, statement generation, and deadline reminders; it’s best when paired with a clear internal checklist and periodic review.
CIS compliance FAQs (verification, deductions, materials, VAT, deadlines, penalties)
How do I verify a subcontractor for CIS?
Verify each subcontractor with HMRC before the first payment. You’ll need their name, UTR (and sometimes NI number or company details). HMRC returns a deduction rate (0%, 20% or 30%) and a verification reference to keep on file.
What payments do I deduct CIS from?
CIS deductions apply to labour and certain related charges (for example, hire of plant with an operator). They generally don’t apply to pure materials, VAT, or equipment hire without an operator. If you’re unsure, treat labour as the default and document your reasoning.
How do materials affect the CIS deduction?
Only deduct CIS from the labour element. If the subcontractor charges for materials, you can exclude the cost of materials from the amount you calculate CIS on—provided the materials are clearly itemised on the invoice.
Do I deduct CIS on VAT?
Where the subcontractor is VAT-registered and charges VAT, CIS is calculated on the amount excluding VAT. Make sure invoices show VAT separately.
When are CIS returns and payments due?
You submit a monthly CIS return for each tax month (6th to 5th). The return is due by the 19th after the tax month ends. Any deductions you’ve made are paid to HMRC as part of your PAYE/NI payment timetable.
What happens if I’m late or make mistakes?
Late returns can trigger automatic penalties, and incorrect deductions can lead to further charges or compliance checks. Keep verification evidence, invoices, deduction calculations, and monthly statements to reduce risk and speed up corrections.