CIS Materials and Labour: Calculations, Rates and Rules

This guide outlines how the UK Construction Industry Scheme applies to materials and labour, explaining the calculation rules, qualifying exclusions, and deduction rates. Learn how to accurately calculate deductions and format subcontractor invoices under HMRC guidelines.

The UK Construction Industry Scheme (CIS) applies strictly to the labour element of construction work, meaning that qualifying materials are completely exempt from any CIS tax deductions. To calculate a CIS deduction, contractors must strip away both VAT and the actual cost of qualifying materials before applying the subcontractor's tax rate.

Key Takeaways: How CIS applies to materials and labour

• CIS deductions never apply to qualifying materials incorporated into the construction work.
• VAT must always be excluded from the invoice total before calculating any CIS tax liabilities.
• Deductions are calculated and processed solely on the remaining labour element of the subcontractor pay.
• Contractor calculations require a clear split between labour fees and material expenses to prevent overpayments.

Does CIS apply to materials?

No, CIS deductions do not apply to materials purchased by a subcontractor and used on a construction project. According to HMRC guidelines, deductions are calculated strictly on the labour portion of the invoice to ensure subcontractors are not taxed on their direct capital outlays.

The main purpose of this exclusion is to prevent taxing a business on its essential physical overheads. When a subcontractor purchases bricks, timber, or electrical cables, these items are treated as non-taxable qualifying materials. Contractors must subtract the direct cost of these items from the gross invoice total before they apply any tax deductions.

What is the CIS materials vs labour calculation formula?

The CIS materials vs labour calculation formula is the official HMRC legal method used to determine the exact amount of tax to deduct from a subcontractor's invoice. Following this standard calculation process ensures that the contractor remains fully compliant with UK tax law.

1. Identify the gross invoice payment amount and exclude any Value Added Tax (VAT) entirely from the calculation.
2. Deduct the actual cost of qualifying materials, which must represent the direct amount spent by the subcontractor on items incorporated into the build.
3. Isolate the remaining balance, which represents the taxable labour element of the invoice.
4. Apply the subcontractor's specific CIS tax rate to this taxable labour balance to find the final deduction amount.

What are the latest CIS deduction rates for subcontractors?

CIS tax rates in the UK depend entirely on the registration status of the subcontractor at the time HMRC verifies their details. Contractors must check this registration status before making any payments to ensure the correct rate is applied and recorded legally.

What counts as qualifying materials under CIS?

Qualifying materials under CIS are goods and consumable parts purchased by the subcontractor that become permanently integrated into the structure under construction. Under the HMRC CIS 340 guide, these items must be chemically or structurally incorporated, or completely used up during the project.

Worked examples: How to calculate your CIS deductions

These physical calculation examples show exactly how contractors must apply CIS rules in different scenario structures to remain compliant. The following examples apply a standard 20% deduction rate to the calculated labour figures after matching exclusions.

Example 1: Labour-only invoice (registered subcontractor)

A standard unregistered or registered plasterer submits an invoice for a total of £2,000 covering labour costs only. Since there are no physical material costs to deduct, the tax rate applies directly to the entire invoice balance.

Example 2: Labour and materials invoice (registered subcontractor)

An electrician submits a total invoice of £4,500 consisting of £1,500 in physical materials and £3,000 in skilled labour. The contractor must remove the cost of materials before calculating the final tax deduction.

Example 3: VAT-registered subcontractor invoice

A carpenter submits an invoice for £7,200 gross, which includes £1,200 of VAT and £2,000 in qualifying materials. The contractor is legally obligated to strip out the VAT first, then deduct materials, before estimating tax on the remainder.

How should subcontractors format invoices for CIS?

Subcontractors must cleanly format their invoices to ensure contractors can easily distinguish between taxable labour and qualifying material costs. Proper formatting prevents the contractor from over-deducting tax on items that should be excluded.

• Create separate, itemised lines showing the exact cost of labour and the exact cost of qualifying materials.
• Ensure VAT is shown as a completely separate line item from the basic labour and materials figures.
• Keep and organize all original material receipts to verify costs if requested by the contracting business.
• Prepare for upcoming compliance shifts, such as the HMRC nil-return monthly reporting rules coming in 2026.

What should a contractor do if a subcontractor doesn't provide receipts?

If a subcontractor fails to provide receipts, the contractor must make a reasonable estimate of the material costs incurred. HMRC expects the contractor to determine a realistic market cost for the materials based on standard pricing.

Contractors must ensure this estimated calculation is realistic and not overstated to avoid potential penalties during an HMRC compliance audit. If the estimate of materials is lower than the subcontractor's claim, the contractor must apply the CIS deduction to the remaining higher balance.

Does CIS get deducted from VAT?

No, CIS deductions are never taken from VAT. Contractors must exclude the VAT portion of an invoice before calculating and preparing the CIS tax deduction.

Can I claim plant hire or scaffolding as a material cost under CIS?

No, you cannot claim plant hire or scaffolding as materials. HMRC rules state that hired machinery, tools, and temporary structures do not qualify for material exclusions.

What happens if I combine labour and materials into a single figure on my invoice?

If you combine these into a single figure, the contractor is required by HMRC to deduct CIS tax from the entire combined amount, resulting in a higher tax deduction.

How do CIS deductions work for a subcontractor with Gross Payment Status?

Subcontractors with Gross Payment Status receive their full invoice payment without any CIS tax deductions. The contractor still records the payment but applies a 0% deduction rate.

When do the new CIS nil return regulations come into effect?

The new CIS nil-return regulations come into effect on 6 April 2026, making it mandatory for contractors to submit monthly nil returns when no subcontractor payments are made.