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CIS Calculator UK: 0%, 20% and 30% Rates

Estimate the CIS deduction and net payment before VAT. Enter the amount subject to CIS, keep allowable direct materials separate, and use the rate HMRC gives you when you verify the subcontractor.

Fact-checked against HMRC guidance on 26 September 2026

CIS Deduction Calculator

Calculate Construction Industry Scheme deductions

Use figures before VAT. The rate must match HMRC's verification result.

£

Enter labour plus the allowable direct materials included below. Do not include VAT.

£
£

Labour + materials should equal the gross payment above. Keep evidence for any amount you exclude from the deduction calculation.

Enter the gross payment and labour amount, or load the example, to see the deduction.

How the CIS calculation works

A contractor starts with the total invoice, removes VAT, and then removes costs that HMRC allows to be excluded. The verified CIS rate is applied to what remains. In this calculator, enter that remaining amount as labour and enter supported direct materials separately.

CIS deduction = amount subject to CIS × verified rate

Is CIS calculated before or after VAT?

Before VAT. HMRC says VAT should be removed from the invoice total before the CIS deduction is calculated. This tool deliberately has no VAT input, so the result is labelled before VAT. Check domestic reverse charge or other VAT treatment separately when you prepare the invoice.

Which costs can be excluded?

HMRC permits the actual cost of materials the subcontractor paid for directly, plus certain specified costs such as some consumable stores, fuel and plant hire. Evidence matters. Do not exclude a charge merely because an invoice calls it “materials” or “equipment”. See the official deduction guidance and detailed CIS 340 examples before relying on an exclusion.

Which CIS rate should you use?

0%

Gross payment status

Use only when HMRC verification returns gross payment status.

20%

Registered

The standard rate for a registered subcontractor.

30%

Unregistered

The higher rate when HMRC cannot match or verify registration.

Do not choose a rate from the subcontractor's invoice. Contractors should verify the subcontractor with HMRC and use the result returned.

How to use this CIS calculator

  1. Verify the subcontractor and note the 0%, 20% or 30% rate HMRC returns.
  2. Enter the gross payment amount before VAT.
  3. Enter the amount subject to the CIS deduction.
  4. Enter allowable direct materials paid for by the subcontractor and keep the evidence.
  5. Select the deduction rate HMRC gives you when verifying the subcontractor.
  6. Check the estimate, then review VAT treatment in the invoice generator. This calculator has no VAT input.

CIS calculation example

A payment before VAT is £1,200: £1,000 is subject to CIS and £200 is supported allowable materials. At the 20% rate:

  • CIS deduction: £1,000 × 20% = £200
  • Net amount before VAT: £1,200 − £200 = £1,000
  • Amount withheld for HMRC: £200

Use the Use example button above to load these values.

Turn the checked figures into an invoice draft

Once the figures balance, use “Review these CIS lines in an invoice”. Experi carries the labour, materials and selected rate into the free invoice generator without creating an account. Nothing is issued, sent or filed with HMRC.

Calculate and review

Statements and records after the calculation

If a contractor makes a deduction, HMRC says the subcontractor must receive a payment and deduction statement within 14 days after the end of the tax month. Contractors must also keep CIS records for at least three years after the end of the tax year they relate to. Read HMRC's CIS record-keeping guidance for the details. The result above is an estimate, not the required statement.

CIS calculator questions

What are the 0%, 20% and 30% CIS rates?

HMRC normally tells the contractor to use 20% for a registered subcontractor, 30% for an unregistered subcontractor, or 0% when the subcontractor has gross payment status. Verify the subcontractor and use the rate HMRC returns.

Is CIS calculated before or after VAT?

CIS is calculated before VAT. Start with the invoice total and remove VAT before working out the amount subject to the CIS deduction. Review domestic reverse charge VAT separately because this calculator has no VAT input.

What materials can be excluded from a CIS deduction?

Use the actual cost of allowable materials the subcontractor paid for directly, supported by evidence. HMRC guidance also lists specific costs such as certain consumable stores, fuel and plant hire. Do not assume every materials or equipment charge is automatically excluded.

How do I calculate a 20% CIS deduction?

Multiply the amount subject to the deduction by 20%. For example, if £1,000 is subject to CIS, the deduction is £200 and the net amount before VAT is £800, plus any allowable materials excluded from the calculation.

Do contractors need to give a CIS payment and deduction statement?

When a contractor makes a deduction, HMRC says the subcontractor must receive a payment and deduction statement within 14 days after the end of each tax month. This calculator produces an estimate, not that statement.

Can a subcontractor claim CIS deductions back?

CIS deductions are advance payments towards the subcontractor's tax and National Insurance. How they are claimed depends on whether the subcontractor is a sole trader, partner or limited company.

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