A business number (BN) and an HST number are not the same thing. The BN identifies your business at CRA. An HST account is one particular program account attached to that identifier. You may need one, several, or none of the additional CRA program accounts depending on your work.
Starting a business does not automatically mean you must open an HST or payroll account on day one.
Decode the letters and numbers
A typical CRA BN has nine digits. Program accounts extend that number, such as RT0001 for GST/HST, RP0001 for payroll, or RC0001 for corporation income tax. The letters identify the tax program; the final digits distinguish accounts.
Example: a corporation might hold the same nine-digit BN for its RC, RT and RP accounts. These are distinct obligations with separate returns or remittances, despite sharing the core BN.
When do you need an HST account?
Many businesses can remain unregistered small suppliers until taxable revenues exceed $30,000 under CRA's calendar-quarter/four-quarter tests, though voluntary registration may be possible. Taxi and commercial ride-share drivers have special rules from the first qualifying fare.
Never charge HST merely because the business has a BN. Confirm the RT registration and its effective date first.
When is a payroll account required?
If you hire employees and must withhold income tax, CPP and EI, you generally need a payroll deductions program account and must remit on the applicable schedule. Paying a genuine independent contractor is different, but misclassification carries risk.
Example: a sole proprietor doing their own consulting work is not their own employee for CPP/EI withholding. Hire a receptionist as an employee and payroll obligations can begin.
What about corporation income tax?
Incorporation usually leads to an RC corporate tax account and a T2 filing obligation, even if the corporation has little or no income. An unincorporated sole proprietor typically reports business income on T1/T2125 instead.
A business name registered with Ontario and a CRA program account serve different purposes. Provincial registration alone does not complete federal tax setup.
A sensible setup order
Identify your legal business form; obtain or confirm your BN; check whether RT, RP, RC, or import/export accounts apply; record each account's effective date; and add filing/remittance deadlines to your calendar.
Keep your incorporation/registration documents and CRA confirmation notices together so your bookkeeper can distinguish every program.
Sources and further reading
General educational content only. Verify current CRA and provincial guidance before acting.