CIS deduction calculator
Free, no sign-in. Nothing you type is stored or sent anywhere — it's all worked out in your browser.
Not legal or tax advice — check your contract. Your contract terms and the facts of your job can change the answer.
How this works
Deduct qualifying direct costs from the invoice excluding VAT, then apply the HMRC-verified 0%, 20% or 30% rate. These rates are unchanged for 2026/27. VAT is never part of the CIS deduction.
Use the subcontractor’s direct cost for materials, consumable stores, job fuel (not travelling), hired plant and manufacturing/prefabrication. Do not deduct a notional charge for the subcontractor’s own plant.
With normal VAT, net payment is the ex-VAT invoice plus VAT less CIS. With domestic reverse charge, the supplier collects no VAT; the customer accounts for it.
FAQs
Who chooses the rate?
HMRC verification establishes gross payment status, 20% registered or 30% unregistered; the contractor does not choose it.
Can I deduct VAT or my own plant charge?
No. VAT is excluded and notional own-plant charges are not qualifying direct material costs.
What changes for public bodies in April 2026?
From 6 April 2026, payments to local authorities and certain public bodies as subcontractors are outside CIS. Check the statutory definition in HMRC CISR13040.
Does reverse charge change CIS?
It changes who accounts for VAT, not the CIS calculation on the ex-VAT amount after qualifying costs.
Civvio works this out automatically from your contract and site records.
Upload the contract and keep your diary, and Civvio flags the dates, notices and money at risk on every job — for you to review before anything is sent.
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