How to Validate UK VAT Numbers, NINO, Company Numbers and UTR in Any Language (2026)
If you're building software for the UK market, you'll eventually need to validate fiscal and identification documents. This guide covers the algorithms, code examples, and the fastest way to add validation to any project.
What are these documents?
VAT number — Tax ID for UK businesses registered for VAT. Format: GB + 9 digits (e.g. GB123456789)
NINO — National Insurance Number, used for tax and social security. Format: 2 letters + 6 digits + letter (e.g. AB123456C)
