How to verify a subcontractor
Before you pay a new subbie, you check them with HMRC. HMRC tells you which CIS rate to use.
When you must verify
- Before you pay a new subbie for the first time.
- For a subbie you have used before, only if they have not been on one of your CIS returns in this tax year or the last 2 tax years.
What you need from the subbie
- Sole trader: their name, UTR and National Insurance number. A temporary NI number cannot be verified.
- Limited company: the company name, the company UTR and the company registration number.
- Partnership: the trading name, the partnership UTR and the nominated partner's details.
The details must match exactly what the subbie gave HMRC when they registered.
How to do it
Use HMRC's CIS online service or CIS software. HMRC gives you the rate and a verification number. Keep the number.
What the answer means
- 20%: registered for CIS.
- 30%: not registered, or HMRC could not match the details.
- 0%: gross payment status. Pay in full.
Subbo cannot check a subbie with HMRC yet. You check on HMRC's own service, then type the rate and verification number into Subbo. Subbo then uses that rate every week.
We checked this against the sources below on 24 Oct 2026. Rules change. You stay responsible for your own tax, so check anything unusual with your accountant or on gov.uk.
Sources
- GOV.UK, "What you must do as a Construction Industry Scheme (CIS) contractor" (gov.uk/what-you-must-do-as-a-cis-contractor)
- HMRC, "Construction Industry Scheme: a guide for contractors and subcontractors (CIS 340)" (gov.uk/government/publications/construction-industry-scheme-cis-340)
Let Subbo do this every week
Subbo works out the CIS for every subbie, builds the pay run and keeps your checks. Free 8-week trial for a few friendly firms.
Free for 8 weeks. No card. No contract. The button opens your email app. Or write to harry@subboapp.com.