CIS deduction calculator

CIS comes off the labour only. Materials are left alone. Put the two in separately and you get the deduction, what the contractor pays HMRC, and what you're left with.

Labour on the invoiceYour work, excluding VAT. This is the only part CIS touches.

Materials on the invoiceWhat you actually paid for materials, plant hire and consumables for this job. Include the VAT if you're not VAT registered, leave it out if you are. Travel and fuel to get there count as labour.

Your CIS status

Labour: £1,000.00
Materials: £400.00
Invoice before VAT: £1,400.00
CIS deducted (20% of labour): − £200.00
You get paid (before any VAT): £1,200.00

The contractor pays £200.00 straight to HMRC against your tax bill. It isn't lost, it's paid early. Materials are left alone, which is why they go in separately.

Your app can do this every time, without you

This is the same sum InstaQuote runs on a real invoice. It splits labour from materials on its own, takes the CIS off, handles the reverse charge wording, and keeps the VAT return in order behind the scenes. You do the job, we do everything else.

Try it free

The other free ones

VAT reverse charge checker

Six questions, and the wording your invoice needs if it applies.

Flat Rate or Standard?

Your turnover and your costs, both schemes, which one leaves you more.

A guide, not tax advice. Rules and rates from GOV.UK, checked 22 September 2026. If a job is unusual or a lot of money rests on it, ask your accountant or HMRC.