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CIS Deduction Calculator

Work out the Construction Industry Scheme deduction on a subcontractor invoice — with materials, plant and consumables taken out first, the way HMRC requires.

The invoice

Verify every subcontractor with HMRC before the first payment. Unverified means 30%.
£
The work itself, excluding VAT.
Comes out before the deduction
£
Bought for this job, at cost. Includes manufacturing or prefabricating materials.
£
Equipment hired in for the job — not kit the subcontractor already owns.
£
Used up on the job. Fuel for plant counts; fuel for travelling does not.
VAT
Between two VAT-registered businesses inside CIS, the reverse charge normally applies — the contractor accounts for the VAT, not the subcontractor.

The deduction

CIS deduction
£300
20% of £1,500 labour
Invoice total (ex VAT)£2,000
Less materials, plant & consumables−£500
Subject to deduction£1,500
CIS deducted−£300
VAT (reverse charge)£0
Net payment to subcontractor£1,700

How the CIS deduction works

Under the Construction Industry Scheme, a contractor doesn’t pay a subcontractor the full invoice. They hold back a percentage and pay it to HMRC, where it sits against the subcontractor’s tax bill. The part people get wrong is what the percentage applies to.

It is never the whole invoice. HMRC’s instruction to contractors is to take the gross amount and remove the parts that aren’t labour before applying the rate.

The three rates

StatusRateWhen it applies
Registered20%Subcontractor is registered under CIS and verified by the contractor with HMRC.
Not registered30%Subcontractor isn’t registered, or HMRC can’t match them when the contractor verifies.
Gross0%Subcontractor holds gross payment status. Paid in full; settles tax through Self Assessment or Corporation Tax.

What comes out before the percentage

Excluded — no deduction

  • VAT
  • Materials the subcontractor paid for
  • Manufacturing or prefabricating materials
  • Plant hired in for the job
  • Consumable stores, once used up
  • Fuel used, other than for travelling

Not excluded — deduction applies

  • Tools and equipment kept and reused
  • Protective clothing and safety equipment
  • Fuel for travelling to and from site
  • Any mark-up added to materials

That last one catches people. Materials come out at cost. If a subcontractor buys £500 of cable and invoices it at £600, the £100 of mark-up is not a material cost — it is part of what they earned, and it is subject to deduction.

CIS and the VAT reverse charge

Since March 2021, most construction services between two VAT-registered businesses operating within CIS fall under the domestic reverse charge. The subcontractor doesn’t charge VAT; the contractor accounts for it on their own return. The invoice says the reverse charge applies and shows the VAT rate that would have applied.

It doesn’t change the CIS sum at all — VAT was never part of the amount the percentage applies to. What it changes is cash flow: the subcontractor no longer holds the customer’s VAT between the invoice and their VAT return. For a business used to that money sitting in the account, the adjustment is real.

The reverse charge doesn’t apply to end users or intermediary suppliers — broadly, a customer who isn’t themselves passing the construction service on. If you’re working direct for a homeowner, you charge VAT normally.

What the contractor has to give the subcontractor

A payment and deduction statement, within 14 days of the end of each tax month, showing the gross amount, the materials taken out, and the amount deducted. Subcontractors need these to prove what has already been paid on their behalf — without them, reclaiming an overpayment at year end becomes an argument.

Related reading

This is a guide, not tax advice. It follows HMRC’s published rules on what to exclude before applying the CIS percentage, but every job has its own facts. For anything material, check with your accountant or with HMRC directly. Yoley Limited isn’t a tax adviser.

Rates and exclusions checked against HMRC guidance on 16 September 2026 — gov.uk: make deductions and pay subcontractors.

CIS on every invoice, worked out for you.

Yoley applies the right deduction automatically when you invoice a subcontractor, keeps a running CIS log by month, and exports it for your CIS300 return. Free, with no monthly fee.

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