- When a corporation is incorporated under the OBCA, Ontario's corporate registry — the Ontario Business Registry — assigns it an Ontario Corporation Number.
- The Business Number is a numeric identifier issued by the Canada Revenue Agency, used to identify a business for its various federal program accounts — corporate income tax, GST/HST,…
Incorporate a business in Ontario and you'll quickly end up holding more than one identifying number — and it's easy to mix them up. The Ontario Corporation Number vs. Business Number question comes up constantly, usually the first time a form asks for one and the owner isn't sure which number it actually wants.
They come from different governments, serve different purposes, and mixing them up on a form can genuinely slow things down.
The Ontario Corporation Number (OCN)
When a corporation is incorporated under the OBCA, Ontario's corporate registry — the Ontario Business Registry — assigns it an Ontario Corporation Number. This number identifies the corporation within Ontario's own registry: it's what you use to look the corporation up in a corporate profile search, file annual returns and change-of-information filings under the Corporations Information Act, and reference the corporation in any dealings with the Ontario registry. It's a provincial corporate-record identifier, not a tax number. A CBCA federal corporation gets an equivalent federal corporation number from Corporations Canada instead, plus its own Ontario registration if it registers extra-provincially here.
The CRA Business Number (BN)
The Business Number is a numeric identifier issued by the Canada Revenue Agency, used to identify a business for its various federal program accounts — corporate income tax, GST/HST, payroll source deductions, and import/export, among others. Each program account is tracked as an extension of the same base BN. The BN is a tax and program identifier, not a corporate registry identifier — it exists for corporations, sole proprietorships, and partnerships alike, whenever any of them needs a federal program account.
Side-by-Side
| Ontario Corporation Number | CRA Business Number | |
|---|---|---|
| Issued by | Ontario government (corporate registry) | Canada Revenue Agency |
| Identifies | The corporation within Ontario's registry | The business, for federal tax and program accounts |
| Used for | Annual returns, corporate filings, name/profile searches | GST/HST, payroll, corporate tax, import/export accounts |
| Exists for non-corporations? | No — only issued to corporations | Yes — sole proprietors and partnerships can have one too |
| Issued automatically together? | Not as a single combined process — the two are issued by different bodies for different purposes | See left |
Why the Distinction Actually Matters
Government forms, bank applications, and contracts sometimes ask for one number specifically, and the other simply won't work in that field — using the wrong one can cause delays or a rejected submission. It's also worth understanding that having an OCN doesn't mean you're automatically registered for the CRA program accounts your business actually needs. Registering for GST/HST once you're at or over the small-supplier threshold, or setting up a payroll account once you have employees, typically has to happen under your Business Number, sometimes as a step separate from incorporation itself.
Practical Tips for Keeping Them Straight
- [ ] Keep both numbers recorded in your corporate minute book alongside your certificate of incorporation
- [ ] Confirm which number a specific form or application is actually asking for before you submit it
- [ ] Register for the specific CRA program accounts your business needs — GST/HST, payroll, and so on — rather than assuming incorporation covered it automatically
- [ ] Update your registered or head office address with the Ontario registry and with your CRA program accounts separately if either changes, since they aren't necessarily kept in sync with each other
Frequently asked questions
Does incorporating automatically give me a CRA Business Number?
Not necessarily as a single combined step — they're issued by different levels of government for different purposes. Many businesses arrange for a BN around the time of incorporation, but you may need to apply for the specific CRA program accounts you actually need, like GST/HST or payroll, separately once you need them.
Which number do I need to register for GST/HST?
GST/HST registration is handled through your CRA Business Number, not your Ontario Corporation Number — the OCN is a provincial registry identifier, not a federal tax account.
Does a sole proprietorship have an Ontario Corporation Number?
No. Only incorporated entities receive an Ontario Corporation Number, since it's tied to the provincial corporate registry record. A sole proprietorship can still have a CRA Business Number if it needs GST/HST or payroll accounts.
What if I lose track of one of these numbers?
Your Ontario Corporation Number appears on your certificate of incorporation and any Ontario Business Registry filings; your Business Number appears on CRA correspondence and program account registrations. Both should also be kept together in your corporate minute book.
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