What is a business number and does my Ontario corporation automatically get one?

A Business Number (BN) is a unique nine-digit number assigned by the Canada Revenue Agency to identify your corporation for federal tax purposes. Think of it as the corporation's federal tax ID.

When you incorporate an Ontario corporation through ServiceOntario and request it, the province can transmit your incorporation information to the CRA so a Business Number is assigned as part of the process. However, this is not always automatic — it depends on how you incorporate and whether you request the CRA registration. If the BN was not set up at incorporation, you can register directly with the CRA online or by phone at no cost.

The Business Number is the root to which specific program accounts are attached. The main program accounts for most corporations are: the corporate income tax account (ending in -T2), the GST/HST account (-RT), the payroll deductions account (-RP), and the import/export account (-RM) if applicable. Each account is activated separately based on when the corporation begins each type of activity. Your accountant typically coordinates these registrations as part of setting up a new corporation, but as the director, it is useful to understand what accounts exist and confirm they are properly set up.