Business Number vs Corporation Number in Canada: What’s the Difference?
A Business Number (BN) is a nine-digit federal identifier issued by the Canada Revenue Agency (CRA) for tax purposes. A Corporation Number is the identifier assigned by a provincial or federal registry when your business is legally incorporated. That’s the core of the business number vs corporation number distinction: one exists for tax purposes, the other for your company’s legal standing — and incorporated businesses usually end up with both.
We see this mix-up constantly with Ontario business owners who’ve just incorporated and assume their corporation number and BN are the same thing, or that whichever number showed up first must be the “main” one. They’re not interchangeable, and using the wrong one on the wrong form can slow down a filing or a CRA registration. Let’s break down exactly what each number does, who issues it, and how Ontario corporations specifically end up with both.
What is a Business Number (BN)?
A Business Number is a nine-digit number assigned by the CRA to identify your business for federal tax purposes. It’s not a provincial number, every business across Canada that needs to deal with the CRA, whether it’s incorporated in Ontario, Alberta, or anywhere else, uses this same federal system.
Your BN is the foundation for several CRA program accounts, including:
- GST/HST accounts
- Payroll accounts
- Corporate income tax accounts
- Import/export accounts
Each program account is identified by adding a two-letter code and a four-digit reference number onto your nine-digit BN. So if your BN is 123456789, your GST/HST account might appear as 123456789RT0001, and your payroll account as 123456789RP0001. The base nine digits never change, only the suffix differs depending on which program you’re registered for.
Sole proprietors, partnerships, and corporations can all be assigned a BN. It’s the universal federal identifier the CRA uses to track your tax obligations, regardless of how your business is structured.
What is a Corporation Number?
Your Corporation Number is the number assigned to your business when it becomes incorporated. The number will appear on documents like your Articles of Incorporation and Certificate of Incorporation. You can be incorporated federally through Corporations Canada or provincially through the OBR.
The Corporation Number does not have anything to do with taxes. Instead, the Corporation Number is used by both federal and provincial authorities as a means to track your corporation’s filings. These filings could include such things as annual filings, changes of address, directors, etc. The Corporation Number will be tied to your business for the life of the corporation if you incorporate your business in Ontario.
Only incorporated businesses receive a Corporation Number. If you’re operating as a sole proprietorship or general partnership, you won’t have one, since those structures don’t create a separate legal entity the way incorporation does.
Key Differences Between Business Number and Corporation Number
Here’s a side-by-side look at how these two numbers compare:
| Feature | Business Number (BN) | Corporation Number |
| Issued by | Canada Revenue Agency (CRA) | Corporations Canada (federal) or a provincial registry like the Ontario Business Registry |
| Purpose | Tax identification (GST/HST, payroll, corporate tax, import/export) | Legal identification of an incorporated entity |
| Scope | Federal — used the same way across all of Canada | Federal or provincial, depending on where you incorporated |
| Who gets one | Sole proprietors, partnerships, and corporations | Only incorporated businesses |
| Found on | CRA correspondence, My Business Account, tax filings | Articles of Incorporation, Certificate of Incorporation, registry filings |
| Changes over time? | The base nine digits stay the same for the life of the business | Stays with the corporation permanently once assigned |
Do Ontario Corporations Get Both Automatically?
Yes, and this is usually where the confusion starts. When you incorporate in Ontario, the province assigns your Corporation Number as part of the incorporation process, and the CRA separately and automatically issues a Business Number to your new corporation so it can be tracked for corporate income tax purposes.
You don’t need to apply for the BN yourself just to have it exist, it gets created in the background as part of incorporating. However, that initial BN only covers the corporate tax program. If you also need to register for GST/HST or set up a payroll account (say you’re hiring your first employee at your Ottawa-based consulting firm or opening up online sales for your Hamilton retail shop), you’ll need to add those specific program accounts to your existing BN through the CRA.
So the short version: incorporating in Ontario gets you a Corporation Number from the province and a baseline BN from the CRA at the same time, but any additional tax program accounts still need to be set up separately.
Where to Find Your Corporation Number
If you’ve already incorporated in Ontario and need to track down your Corporation Number, check these sources first:
- Your Articles of Incorporation — this is the document issued at the time of incorporation, and the number is printed clearly on it
- Your Certificate of Incorporation
- A Corporate Profile Report, which you can order through a search of the Ontario Business Registry
- Past Annual Return filings, if you’ve filed one before
If your corporation has misplaced its founding paperwork entirely, an Ontario Business Registry search by business name will pull up the number, or you can work with an intermediary to retrieve it. One thing worth flagging: if your corporation was registered before the Ontario Business Registry launched in October 2021, your records were migrated into the new system, so your number should still be searchable even though the registry itself has changed.
Where to Find Your Business Number
Your BN typically shows up in a few predictable places:
- The CRA’s welcome letter, sent shortly after a corporation is registered.
- Your CRA My Business Account login, where it’s listed alongside any program accounts you’ve set up.
- Notices of assessment or reassessment for corporate tax.
- Any GST/HST or payroll registration confirmation, where it appears as a suffix on the base nine digits.
If you’ve lost track of it, the CRA can confirm it by phone once they verify your identity, or it can be retrieved through an authorized representative if you’ve set one up on your account.
Frequently Asked Questions
Is a Business Number the same as a Corporation Number?
No. The BN is a federal tax identification number, whereas the Corporation Number is a legal number assigned to a corporation upon incorporation. These numbers have different uses and are assigned by different organizations.
Do I need both a Business Number and a Corporation Number
Yes, if you are incorporated. The Corporation Number is used to identify your legal entity, whereas the BN will be used for any tax accounts that your business requires.
Where do I find my Ontario corporation number?
Check your Articles of Incorporation or Certificate of Incorporation first. If those aren’t available, a search through the Ontario Business Registry by business name will locate it.
Does incorporating in Ontario give you a Business Number automatically?
Yes. Once your corporation is registered with the province, the CRA automatically issues a baseline BN tied to your corporate tax account. You’ll still need to register separately for things like GST/HST or payroll if your business requires them.
Can a sole proprietor have a Corporation Number?
No. A Corporation Number is only issued to incorporated entities. Sole proprietors may have a BN if they’re registered with the CRA, and in Ontario, they may also have a Business Identification Number tied to a registered business name — but neither of those is a Corporation Number.
What format is a Corporation Number in?
A Corporation Number is typically 7 to 8 digits, with the exact length depending on whether you incorporated federally through Corporations Canada or provincially through a registry like the Ontario Business Registry. This is shorter than a BN, which is always nine digits. You can confirm your exact number on your Articles of Incorporation
The Bottom Line
Untangling these two numbers gets a lot easier once you remember what each one is actually for:
- A Business Number is federal, tax-focused, and issued by the CRA, every business type can have one, not just corporations.
- A Corporation Number only exists if your business is incorporated, and it’s tied to your legal standing with a provincial or federal registry.
- Incorporating in Ontario typically generates both numbers around the same time, but additional CRA program accounts (HST, payroll) need to be added separately.
- Your Articles of Incorporation is the fastest place to find your Corporation Number; your CRA account or correspondence is the fastest place to find your BN.
- When in doubt about which number a form is asking for, check whether it’s a tax-related filing (BN) or a corporate registry filing (Corporation Number).
Getting these two straight from the start saves a surprising amount of back-and-forth down the line, especially once your business starts juggling multiple filings, accounts, and government touchpoints at once.
