How to Find My GST Number

by Catherine Lovering; Updated September 26, 2017

The Canada Revenue Agency issues Business Numbers to registered businesses. The BN is the only number businesses use to identify themselves when communicating with the federal government. It provides access to all business-related accounts, including the GST. As of July 2015, you can contact the CRA about your BN or GST account by phone or online.

The BN is a 9-digit number. Your GST account with the CRA will have 16 digits, made up of your BN, the letters RT to indicate a GST account, followed by four unique numbers.


  • The BN is different from the Business Identification Number. The BIN is used in Ontario to identify provincial business accounts.

If you cannot locate your BN or GST account number you can contact the CRA at 1-800-959-5525. Otherwise, you can review your business documentation to find the number. If you require an access code to review your GST account online, you can contact the CRA at 1-877-322-7849 from within Canada, or 613-940-8528 if you are calling from outside North America. You can also visit the Access Code Online website.

Check Your Paperwork

Your BN must appear on all transaction paperwork, such as receipts, invoices and contracts totalling $30 or more. Review these items from your business records to locate your BN. You can also review paper or electronic copies of your business tax returns.


  • In an FAQ document about the GST/HST Registry, the CRA says the terms GST/HST account number, Business Number and registration number are used interchangeably. This Registry is intended for businesses and individuals to verify the GST registration of a supplier, and requires users to input the business name and BN.

Get an Access Code Online

To access your GST account online, you will need an Access Code. You should have received it in the mail. If it has been misplaced, you can enter certain information on the Access Code Online website to get a new number. You must enter your BN and the reporting period of the return you need to access online. You must also enter either:

  • The line 109 (net tax) amount from a previous return, provided that amount is not $0, or;
  • The confirmation number from a return provided electronically.

Alternatively you can call the CRA e-Services Help Desk at 1-877-322-7849 or 613-940-8528 outside North America.

About the Author

Catherine Lovering has written about business, tax, careers and pets since 2006. Lovering holds a B.A. (political science), LL.B. (law) and LL.L. (civil law).