Canadian Business Number (BN) Regex for JavaScript

What this pattern does

This page provides a well-structured, multi-part regular expression for matching canadian business number (bn), 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

// Canadian Business Number (BN)
// ReDoS-safe | RegexVault — Finance > Tax & Registration

const canadianBusinessNumberBnRegex = /^[0-9]{9}(?:[A-Z]{2}[0-9]{4})?$/;

function validateCanadianBusinessNumberBn(input: string): boolean {
  return canadianBusinessNumberBnRegex.test(input);
}

// Example
console.log(validateCanadianBusinessNumberBn("123456789")); // 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

The 9-digit root identifies the business. Program identifiers: RT (GST/HST), RP (payroll), RC (corporate income tax), RZ (information returns). The 4-digit reference number distinguishes multiple accounts of the same type.