Free tool
Free CIS deduction calculator
Enter the gross amount (excluding VAT), the qualifying materials cost and the subcontractor's verification status. The calculator applies HMRC's CIS rules — 20% verified, 30% unverified, 0% gross status — to the labour element only and shows the deduction and net payment.
- Amount liable to CIS (gross − materials)
- £0.00
- CIS deduction (20%)
- − £0.00
- Net payment to subcontractor
- £0.00
VAT is never included in the CIS calculation. The deduction is rounded down to the penny. Pay the deducted £0.00 to HMRC with your monthly CIS return.
Guidance tool only. Full rules: GOV.UK — make deductions and pay subcontractors.
Frequently asked questions
- How is a CIS deduction calculated?
- Take the gross payment excluding VAT, subtract the cost of qualifying materials, then apply the subcontractor's rate to what is left: 20% if HMRC has verified them, 30% if not, or 0% if they hold gross payment status. VAT is never part of the calculation.
- What counts as qualifying materials under CIS?
- Materials the subcontractor actually bought to complete this specific job — including the VAT they paid on them if they are not VAT-registered, plus consumables, fuel for plant (not travel) and plant hire they paid for. It is what the materials genuinely cost them, not a standard percentage.
- When do I deduct 30% instead of 20%?
- You must deduct 30% when you cannot verify the subcontractor with HMRC — for example the details they gave you don't match HMRC's records, or they aren't registered for CIS. Once HMRC verifies them, the rate drops to 20%, and subcontractors with gross payment status are paid with no deduction at all.
- What do I do with the amount I deduct?
- Pay it to HMRC and report it on your monthly CIS return (due by the 19th of the following month), and give the subcontractor a payment and deduction statement. The deduction counts towards the subcontractor's tax and National Insurance.
Valegrid Flow runs your whole CIS payroll from approved timesheets — statements, exports and monthly figures included.
See CIS payroll