Home Business Number (BN) Canada
Canada Business Number (BN) validator
How the Business Number (BN) format works
- Format
- 9 digits with a standard Luhn check digit
- Example
- 123456782
Things to watch for
- This validates the 9-digit BN root only — program-account suffixes like RT0001 (GST/HST) or RP0001 (payroll) aren't part of the checksum
- Checksum only — a pass doesn't confirm the BN is currently registered or active with the CRA
- This check runs entirely in your browser, so nothing you type is stored or transmitted
^[0-9]{9}$The Business Number (BN) is the 9-digit identifier the Canada Revenue Agency (CRA) assigns to a business the first time it registers for a CRA program account — corporate income tax, GST/HST, payroll deductions, or import/export. Every business gets exactly one 9-digit BN root, for example 123456782, no matter how many different CRA programs it later registers for.
The root plus program accounts
The BN root by itself isn’t the whole story. Each CRA program a business registers for gets its own program-account identifier, built by appending a 2-letter program code and a 4-digit reference number to the same 9-digit root — RT0001 for a business’s first GST/HST account, RP0001 for its first payroll account, RC0001 for corporate income tax, and so on. A business with a GST/HST account and a payroll account shares one BN root across both, extended by two different suffixes.
Why the ninth digit exists
The BN root carries a standard Luhn check digit — the same mod-10 algorithm used to validate credit card numbers — built into all 9 digits together. Every second digit counting from the right is doubled (subtracting 9 from any result over 9), and the total across all 9 digits must land on a multiple of 10; a single mistyped or transposed digit almost always breaks that total.
What this check doesn’t tell you
This tool validates the 9-digit BN root only — it doesn’t check or generate a program-account suffix, and a pass doesn’t confirm the BN is currently registered or active with the CRA. Nothing is stored or transmitted; the check runs entirely in your browser.
Scope: this page and tool cover the 9-digit BN root’s Luhn checksum only — not program-account suffixes or CRA registration status.
Content last reviewed 2026-08-09.
Business Number (BN) FAQ
What's the difference between a Business Number and a GST/HST number?
A GST/HST number is the 9-digit Business Number (BN) root plus the program-account suffix RT0001 (or RT0002 for a second account, and so on) — the BN identifies the business itself, while the RT suffix identifies specifically its GST/HST program account with the CRA.
Does every business have the same 9-digit BN across all its CRA accounts?
Yes. A business keeps one 9-digit BN root for its entire relationship with the CRA; registering for additional programs, such as payroll or import/export, adds new suffixes to that same root rather than issuing a new root number.
How does the Luhn check digit catch typos?
All 9 digits of the BN root, including the check digit itself, run through the Luhn (mod-10) algorithm — the same method used to validate credit card numbers. Every second digit counting from the right is doubled (subtracting 9 from any result over 9), and the total of all 9 digits must land on a multiple of 10. A single mistyped digit almost always breaks that total.