Free CIS tool

CIS Tax Calculator

Work out your CIS deduction and the net pay you'll actually receive. Enter your figures below — it updates instantly.

£
£
Invoice total
£0.00
CIS deducted
£0.00
Net you receive
£0.00

CIS is deducted from labour only — materials are always paid in full. This is an estimate for guidance, not tax advice.

How CIS deductions work

Under the Construction Industry Scheme (CIS), contractors deduct money from a subcontractor's payment and pass it to HMRC. The deduction counts as an advance payment towards the subcontractor's Income Tax and National Insurance.

The deduction only applies to the labour on your invoice. Materials, plant hire, and certain other costs are paid in full — which is why it's important to itemise them separately.

The CIS rates

StatusDeduction
Registered with HMRC for CIS20%
Not registered30%
Gross payment status0%

Worked example

You invoice £1,000 labour + £200 materials, and you're CIS-registered (20%). The contractor deducts 20% of the £1,000 labour = £200. You receive £1,200 − £200 = £1,000, and £200 is paid to HMRC against your tax bill.

CIS calculator FAQs

How is CIS tax calculated? +
The contractor deducts CIS from the labour part of your invoice only — never from materials. Registered subcontractors are deducted at 20%, unregistered at 30%, and gross-status at 0%. It's an advance towards your Income Tax and National Insurance.
Is CIS deducted from materials? +
No — only the labour element. List materials separately so they're paid in full.
20% or 30%? +
20% if you're registered with HMRC for CIS, 30% if you're not, and 0% with gross payment status.
Do I get the deduction back? +
CIS deductions offset your Self Assessment tax bill; HMRC refunds any overpayment after you file.
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