UK UTR (Unique Taxpayer Reference) Regex for JavaScript

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching uk utr (unique taxpayer reference), ported and verified for JavaScript. Financial data validation has zero tolerance for false negatives — a missed invalid entry can corrupt downstream calculations. The snippet below is ready to drop into your JavaScript project — whether you're validating in an Express middleware, a Next.js API route, or a client-side form.

Javascript Implementation

// UK UTR (Unique Taxpayer Reference)
// ReDoS-safe | RegexVault — Finance > Tax & Registration

const ukUtrUniqueTaxpayerReferenceRegex = /^[0-9]{10}$/;

function validateUkUtrUniqueTaxpayerReference(input: string): boolean {
  return ukUtrUniqueTaxpayerReferenceRegex.test(input);
}

// Example
console.log(validateUkUtrUniqueTaxpayerReference("1234567890")); // true

Test Cases

When to use this pattern

This pattern is drawn from the Finance > Tax & Registration category and carries a ReDoS-safe certification. That matters for JavaScript developers because especially critical in long-running Node.js event loops where a ReDoS vulnerability can block the entire process. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Issued by HMRC to individuals and companies for self assessment. Personal UTR and company UTR are both 10 digits but used in different contexts. The first digit of a company UTR indicates the type (0-9).