CIS Deduction Calculator
Enter your labour and materials, pick your CIS status, and see exactly what a contractor will pay you after the deduction. CIS comes off labour only — this does the maths for you.
CIS is deducted from labour only — never materials or VAT.
Do this automatically on every quote →How CIS deductions work
Under the Construction Industry Scheme, a contractor withholds part of your payment and pays it to HMRC as an advance on your tax. It is deducted from your labour only — never materials or VAT — at 20% if you are registered and verified, or 30% if not. You reclaim it through Self Assessment. For the full picture, read how CIS deductions work for electricians and VAT for electricians.
FAQs
How is CIS calculated?
CIS is calculated on the labour portion of your invoice only — never on materials or VAT. The contractor withholds 20% (if you are registered and verified) or 30% (if not) of your labour and pays it to HMRC on your behalf.
Does CIS come off materials?
No. CIS is deducted from labour only. Materials, plant hire and VAT are excluded, which is why you should always itemise labour and materials separately on your invoice.
What CIS rate should I use — 20% or 30%?
20% if you are registered for CIS and the contractor can verify you. 30% if you are not registered or cannot be verified. Registering with HMRC moves you from 30% to 20%.
Is this CIS calculator free?
Yes — completely free and no sign-up required. It uses the same VAT and CIS engine that powers SparkQuote's quoting and invoicing app.
Do this automatically on every quote & invoice
SparkQuote works out VAT and CIS on every job — £15/mo, first 2 quotes free.
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