Free tools for UK trades
CIS deduction calculator
Work out what you’ll take home, or what to invoice. Calculate your Construction Industry Scheme deduction with labour and materials kept separate.
Including materials / excluded costs. Excluding VAT.
Actual allowable costs you paid, not the marked-up charge.
Your CIS breakdown
You receive, before VAT
After a 20% CIS deduction on labour.
- Labour / amount subject to CIS
- £0.00
- Materials / excluded costs
- £0.00
- Invoice total (excluding VAT)
- £0.00
- CIS deduction (20%)
- £0.00
- Payment after CIS (excluding VAT)
- £0.00
Estimate only. VAT is not calculated or included. CIS is an advance payment towards tax, not your final tax bill. This is not an official payment and deduction statement.
Keep more than your accounts in order
Who’s answering while you’re working?
TradeRing answers the calls you miss and sends you the job details. £89/month. 7 days free, no card needed.
How the CIS calculation works
CIS deduction = (invoice before VAT − allowable excluded costs) × deduction rate. Your payment before VAT is the invoice amount minus that deduction.
£1,200 invoice − £200 materials = £1,000 labour. At 20%, £200 is deducted. You receive £1,000 before any VAT.
What counts as an excluded cost?
HMRC permits certain costs you paid directly, including materials, consumable stores, plant hire, fuel (except travel fuel), and manufacturing or prefabrication costs. Only enter costs that qualify, with evidence. The remaining amount is labelled labour in this calculator.
Check HMRC’s deduction rulesCIS calculator questions
How do you calculate CIS deductions?
Subtract VAT and allowable excluded costs from the invoice, then multiply the remaining amount by the CIS rate HMRC gives the contractor. For example, an invoice of £1,200 before VAT with £200 allowable materials leaves £1,000 subject to CIS. At 20%, the deduction is £200 and the payment is £1,000 before VAT.
Is CIS deducted at 20% or 30%?
Usually 20% applies to registered, verified subcontractors. The rate is 30% if you are unregistered or cannot be verified. Gross payment status means 0% is deducted. The contractor must use the rate supplied by HMRC on verification.
Are materials included in CIS deductions?
Allowable materials paid for directly by the subcontractor are excluded. Use the actual cost, not a marked-up selling price. If you are VAT registered, use the cost excluding VAT; if you are not VAT registered, include VAT you paid on those materials. Keep evidence of the costs.
How do I reverse a CIS payment from net to gross?
Subtract materials and allowable excluded costs from the desired payment, divide the remainder by 0.8 for 20% CIS (or 0.7 for 30%), then add the excluded costs back. To receive £1,000 before VAT with £200 materials at 20%, invoice £1,200 before VAT.
Does CIS apply to VAT?
No. VAT is excluded from the CIS deduction calculation. This calculator uses amounts before VAT and does not calculate VAT. Domestic reverse charge VAT may apply to construction services; check the separate VAT treatment with your accountant.
Is this my final tax bill?
No. CIS deductions are advance payments towards tax and National Insurance. Your final liability depends on your full accounts and tax return. This calculator is an estimate, not tax advice or an official contractor payment and deduction statement.
CIS worked examples
| Invoice (before VAT) | Materials | Rate | CIS deducted | You receive |
|---|---|---|---|---|
| £1,000 | £0 | 20% | £200 | £800 |
| £1,200 | £200 | 20% | £200 | £1,000 |
| £2,500 | £700 | 20% | £360 | £2,140 |
| £1,200 | £200 | 30% | £300 | £900 |
| £1,200 | £200 | Gross (0%) | £0 | £1,200 |