CIS Deduction Calculator UK
Calculate the CIS tax deduction on a subcontractor invoice: enter gross labour, materials, and your CIS status to see exactly what the contractor pays you.
How CIS deductions work
Under the Construction Industry Scheme (CIS), contractors deduct tax from the labour portion of your invoice before paying you. Materials and plant are not subject to CIS deduction.
- Registered subcontractor: 20% deducted from gross labour
- Unregistered: 30% deducted — always register with HMRC before starting work
- Gross payment status: 0% deducted (HMRC approval required)
CIS deductions are advance payments of tax — they reduce your Self Assessment or corporation tax bill. The contractor sends the deduction directly to HMRC and must give you a CIS deduction statement within 14 days of each tax month end.
VAT and CIS: domestic reverse charge
When both you and the main contractor are VAT-registered and the work falls under CIS, the domestic reverse charge applies. You do not add VAT to your invoice — instead, the contractor accounts for the VAT on their own return. Your invoice must state: "Reverse charge: customer to account for VAT to HMRC."
Standard-rate VAT (you charge 20%) only applies when the contractor is not VAT-registered. If you are not VAT-registered, no VAT applies regardless. Verify with your accountant if you are unsure which scenario applies.
Ready to quote and invoice properly?
Quotimiser structures labour, materials, travel, tools, overheads, and VAT on every quote — then turns approved work into invoices without retyping figures.
Create free account