Invoice deduction
A contractor or subcontractor working out one payment: the CIS-deductible amount after exclusions, the rate that applies (registered, unregistered or gross), and the net payment. This is not your final tax position.
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CIS deduction and year-end position calculator
Two clearly separate calculators: what should be deducted from a single invoice, and what your estimated Self Assessment position looks like against CIS already deducted this year. Current 2026/27 rates, full working shown, nothing sent anywhere.
CIS calculator
2026/27 rates · checked 2026-08-22
This invoice
£1,760
net payment, ex VAT
- Invoice, ex VAT
- £2,000
- Excluded costs
- £800
- CIS-deductible amount
- £1,200
- CIS deducted at 20%
- £240
The figure above is the net payment excluding VAT, not the total cash payment: if the subcontractor is VAT-registered, VAT is charged and paid separately on top, outside this CIS calculation entirely. The CIS deduction applies only to the deductible amount above, not the whole invoice: materials paid for directly are never part of the calculation. This deduction is an advance payment towards tax and National Insurance, not your final tax bill.
Two different CIS questions, not one
Year-end position
A subcontractor working out where they stand for the whole tax year: an estimated Income Tax and National Insurance liability, set against CIS already deducted, giving an estimated balance due or surplus.
What this calculator does not cover
- Whether CIS applies to your specific contract, or whether a gross payment status application would succeed: see TBV's CIS guide for the eligibility tests.
- Other PAYE income, pensions, student loans, payments on account, or trading losses in the year-end mode. The same scope limits as the self-employed tax calculator apply.
- A guaranteed refund figure. The year-end mode shows an estimated surplus or balance due within its stated assumptions, not a number HMRC has agreed.
Questions subcontractors ask about CIS
Why are there two CIS calculators on this page?
Because they answer genuinely different questions. "What gets deducted from this invoice?" is a contractor's or subcontractor's question about one payment. "What's my estimated year-end position?" is a subcontractor's question about the whole tax year, comparing an estimated final Income Tax and National Insurance liability against what's already been deducted. Treating them as the same calculation is a common, genuine mistake.
Is CIS 20% or 30% of the whole invoice?
Neither, on the whole invoice. The rate applies only to the CIS-deductible amount, after excluding VAT and costs such as materials you paid for directly, plant hire and consumable stores. The invoice-deduction calculator above shows this working, not just the final figure.
Will I get a CIS refund?
Maybe, but this calculator does not promise one. If your CIS deductions this year turn out to be more than your estimated final tax and National Insurance liability, it shows an estimated surplus. If they're less, it shows an estimated balance still due. Either way, it's an estimate within this calculator's stated assumptions, not a guaranteed refund.
What does gross payment status change here?
Selecting it in the invoice calculator sets the deduction rate to 0%: you're paid the invoice in full, and handle Income Tax and National Insurance yourself through Self Assessment. Applying for gross payment status itself is subject to HMRC's turnover, business and compliance tests, covered in TBV's CIS guide, linked below.