Shortly after incorporating, you'll encounter a nine-digit number followed by mysterious letter codes: something like 123456789 RC0001. This is your Business Number system, and understanding it takes five minutes — which is exactly five minutes more than most founders spend, and why so many miss a registration they needed.
The Business Number (BN): Your Corporation's SIN
The nine-digit Business Number is the CRA's single identifier for your business — think of it as your corporation's social insurance number. Federal corporations receive one automatically at incorporation. Provincial corporations in most provinces also get one through data-sharing with the CRA, though occasionally you'll need to register directly.
The BN itself does nothing. The power is in the program accounts attached to it — each one a two-letter code plus a four-digit reference.
RC — Corporate Income Tax
Format: 123456789 RC0001. This account exists for every corporation and is where your T2 corporate tax return is filed and corporate taxes are paid. It's opened automatically. Your T2 is due six months after your fiscal year-end every year, even with zero activity — a nil return is still a required return.
RT — GST/HST
Format: 123456789 RT0001. This is your sales tax account, and it is not automatic — you must register. Registration becomes mandatory once your worldwide taxable revenues exceed $30,000 over four consecutive calendar quarters, but voluntary early registration is often smart: it lets you claim input tax credits on your startup costs. Once registered, you must charge HST/GST on taxable sales and file returns on your assigned schedule (annual for most small corporations). Read our full guide to when to register for HST.
RP — Payroll
Format: 123456789 RP0001. Required before you pay anyone a salary — including yourself. The RP account is where you remit the income tax, CPP, and (for arm's-length employees) EI you withhold from pay. Remittances for regular remitters are due by the 15th of the month after the payday, and T4 slips are due by the last day of February each year. Paying salary without an RP account is a compliance problem from the first paycheque.
The Ones You Might Meet Later
- RM — Import/Export. Needed if you import goods into Canada or export commercially. Registration is free and instant; customs brokers will ask for it.
- RZ — Information returns. Used for filing certain slips like T5s in some setups (many corporations file T5s under the BN directly — your CPA will set this up correctly).
A 60-Second Self-Check
| Your situation | Accounts you need |
|---|---|
| Just incorporated, no revenue yet | RC (automatic) |
| Invoicing clients, under $30K revenue | RC + RT (optional but often smart) |
| Over $30K in trailing revenue | RC + RT (mandatory) |
| Paying yourself or anyone a salary | RC + RP (before first payday) |
| Importing product to resell | RC + RT + RM |
How to Register
All program accounts can be opened through CRA's Business Registration Online in minutes, or by phone. Register your CRA My Business Account portal at the same time — it's how you'll see balances, file returns, and catch CRA correspondence before it becomes a problem. And put every resulting deadline in one place: our Compliance Calendar Builder generates them all from your incorporation date.
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