You do not deduct on the whole invoice

CIS deductions, on labour only

The rate is the easy part. The two things that cause corrections are deducting on materials you should have excluded, and deducting on a VAT-inclusive figure. This does both properly, and tells you when the return is due.

The invoice

Invoice total, excluding VAT

Never the VAT-inclusive figure.

Of which materials

Genuine cost to the subcontractor, excluding VAT.

Subcontractor status

Verify with HMRC before the first payment.

Payment date

Sets which CIS tax month the payment falls in.

VAT on the invoice (for context)

Shown so you can see what NOT to deduct on.

One free calculation per company. Company number and a work email, and this runs through the same CIS engine we use in payroll — deduction, deadlines and the two ways it usually goes wrong.

The working LIVE

What the other two statuses would cost

Status	Rate	Deduction	Subcontractor receives

The deduction is the easy half. The return is the deadline.

A CIS300 is due by the 19th of every month whether or not you paid anyone — a nil return still has to go in, and a missed one is an automatic £100 penalty that escalates. Verification, monthly statements to subcontractors, and the return itself are a recurring obligation, not a calculation.

Run it yourself → We Switch Payroll Have someone run it → We Switch Payroll

Free either way: the calculators stay free and stay in your browser.

The other calculators

Take-home payTax, NI and student loan on a wage Employer costWhat a hire really costs you Holiday pay12.07%, 5.6 weeks, or the 52-week average Auto-enrolmentWho must be enrolled, and for how much Minimum wageAre you actually compliant? Statutory paySSP, SMP, SPP and the rest

The two corrections we see most. First, materials: the deduction applies to the labour element only, so a genuine materials cost must come out of the base before you apply the rate. Over-deducting takes money off a subcontractor that you then have to pay back. Second, VAT: CIS is always calculated on the VAT-exclusive figure — under the domestic reverse charge there may be no VAT on the invoice at all, which is not the same as the materials being zero. A CIS tax month runs from the 6th to the 5th, and the return is due by the 19th. This tool computes; it does not advise, and it does not verify anyone — verification is a call to HMRC before the first payment.