§ VERIFICATION · 6 MIN READ
How to check a UK VAT number — the full guide
The four ways to verify a UK VAT number, with the trade-offs of each.
Published 2026-04-16 · Countersure
Why VAT validation matters
Reclaiming input VAT against an invalid VAT number is one of the most common reasons HMRC denies a VAT return. The cost lands on the buyer, not the seller.
The penalty regime tightened in 2023. HMRC is more willing than ever to assess on the basis of weak supplier verification.
Method 1 — HMRC website
HMRC offers a public lookup at gov.uk. It accepts one number at a time and returns the registered name and address.
It is free, but rate-limited and unsuitable for bulk verification. The output is a screen — not a defensible audit artefact.
Method 2 — VIES
The European Commission VIES service validates VAT numbers across the EU. Post-Brexit, GB-prefixed numbers are no longer routed through VIES — only XI (Northern Ireland) numbers are.
For cross-border EU trade, VIES gives a consultation reference number that constitutes evidence of the check.
Method 3 — Countersure
Countersure calls the live HMRC API for UK numbers and produces a stamped PDF audit artefact in one step. Free for occasional use, paid plans for bulk and API.
The verification ID format CS-YYYYMMDD-XXXXXXXX is unique, traceable, and stable across re-checks.
Method 4 — Tax software integrations
Most modern bookkeeping software offers an integration. Quality varies. Many do not store evidence beyond a tick-box.
For audit defence, you want a stamped artefact — not a checked box.
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