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Review one CIS deduction before you do the whole month.

A common CIS review issue is deducting on the whole payment instead of the labour only, or using the wrong HMRC status. Enter one subcontractor payment below and see the figure produced by the published CIS arithmetic.

Guidance, not advice. This applies published CIS arithmetic to the figures and status you enter; it does not verify the sub with HMRC. Check the current rules on GOV.UK and verify with a qualified professional if unsure.

CIS Single-payment deduction checker 🔒 runs in your browser
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Tip: the most common error is deducting on the gross (£2,400) instead of the labour. Enter that figure to see if you'd have over-deducted.

Nothing is sent anywhere. The maths runs on your device and follows HMRC's published CIS rules.

The rule the checker uses

The deduction is on the labour, not the whole payment.

No magic, no guesswork — here is the arithmetic, following HMRC's published method. Always check the current rules and rates on GOV.UK.

1

Carve out materials

Labour element = gross paid (excl VAT) − the subcontractor's direct material cost. You only ever deduct on this labour figure.

2

Apply the verified rate

Currently 20% if registered & verified · 30% if unverified / not matched · 0% if verified for gross payment (confirm the current rates on GOV.UK). The rate applies to the labour, not the gross.

3

Net = gross − deduction

The subcontractor is paid the gross minus the CIS deduction. That deduction figure is exactly what goes on the statement and into your CIS300 total.

And what's not in it: the VAT domestic reverse charge is deliberately ignored — it belongs on the invoice and VAT return, not the CIS deduction. Enter figures excluding VAT. This checker does the arithmetic for the figures you enter; it does not verify the subcontractor with HMRC or decide what counts as "materials".