CIS Deduction Calculator
For UK subcontractors: see exactly what lands in your bank after the CIS deduction — or flip it and work out what to invoice so you take home the figure you actually need. Free, no signup, nothing leaves your browser.
The deduction isn't lost — it's income tax paid in advance, set against your Self Assessment (or reclaimed). VAT is never deducted from: if the reverse charge applies you charge no VAT anyway; if it doesn't, VAT is added after the CIS sums.
How the CIS deduction actually works
Under the Construction Industry Scheme, a contractor paying a subcontractor must deduct tax from the labour element of the invoice and pass it to HMRC — 20% if you're registered, 30% if you're not, 0% if you hold gross payment status. Materials charged at cost are paid in full. The deduction is your income tax paid in advance, reconciled at year end.
Two practical consequences for the person writing the quote. First, split labour and materials on every quote and invoice — the contractor can't run the deduction without the split, and your payment waits while they ask. Second, price knowing that a fifth of your labour arrives months later as a tax credit: your day rate has to be right before HMRC takes its slice first. The exact sentences to put on your paperwork — including the reverse charge VAT wording — are in our copy-and-paste CIS wording guide.
The reverse mode answers the question most calculators don't: "I need £X in the bank for this job — what do I put on the invoice?" Divide your target by 0.8 (or 0.7 at the 30% rate) and that's your labour line; this tool does it for you. If you quote jobs end-to-end, the free quote generator builds the whole document.
Questions, answered
How much CIS is deducted from my invoice?
20% of the labour element if you're CIS-registered, 30% if you're not, 0% with gross payment status. Materials charged at cost are never deducted from — which is why a CIS invoice must split labour and materials.
Is the CIS deduction calculated before or after VAT?
CIS is calculated on the amount excluding VAT, and VAT is never deducted from. On most subcontractor-to-contractor work the domestic reverse charge applies anyway, so no VAT appears on your invoice at all — the contractor accounts for it.
Do I get the CIS deduction back?
Yes — it's income tax paid in advance, not a fee. Sole traders set it against their Self Assessment bill (and are often due a refund); limited companies offset it against PAYE/CT. Keep the contractor's deduction statements as your evidence.
Why am I being deducted 30% instead of 20%?
Either you're not registered for CIS, or the contractor couldn't verify you — often a mismatch between the name on your invoice and the name registered with HMRC, or a missing UTR. Registering (free) and putting your UTR and exact registered name on your paperwork fixes it.
Does this calculator store my figures?
No. Everything is calculated in your browser as you type — nothing is sent to our servers, stored, or seen by us.