Business Number vs Corporation Number
A licensed Ontario CPA explains the two numbers every incorporated business has, why they come from different governments, what the 15-character CRA format actually means, which number goes on your invoices and your T2, and the setup gap that causes most first-year filing problems.
Quick Answer
They come from two different governments and do two different jobs. Your Corporation Number is issued by the registry where you incorporated (Corporations Canada or a province) and proves your company legally exists. Your Business Number is a 9-digit CRA identifier and is how you file and pay tax. Incorporating gives you the first. It does not automatically give you the CRA accounts you need to file.
Two Numbers, Two Governments, Two Jobs
Almost every incorporated business owner has both numbers and about half of them could not tell you which is which. That is not carelessness. Nothing in the incorporation process explains the distinction, the two numbers arrive at different times from different places, and both look like official identifiers for the same company. The confusion is built into the system.
Here is the distinction that makes the rest of it make sense. Incorporating is a legal act, performed at a registry, that brings a corporation into existence as a separate legal person. That registry gives you a Corporation Number to identify the entity it just created. Filing tax is a separate matter, handled by the Canada Revenue Agency, which maintains its own identity system and issues you a Business Number. The registry does not collect tax. The CRA does not create corporations. Neither system uses the other's number.
| Feature | Corporation Number | Business Number (BN) |
|---|---|---|
| Issued by | Corporations Canada, or a provincial registry such as Ontario | Canada Revenue Agency |
| What it proves | Your company legally exists as a separate entity | Your tax identity with the CRA |
| Format | Varies by registry | 9 digits, extended to 15 characters with program accounts |
| Found on | Certificate of Incorporation, Articles of Incorporation, the public register | CRA correspondence, My Business Account, Notice of Assessment, PD7A |
| Used for | Corporate annual return, corporate records, registry filings | T2, GST/HST, payroll, every CRA filing and payment |
| Do sole proprietors have one? | No, they have not incorporated | Yes, once they register for HST, hire, or import |
| Goes on invoices? | No requirement | Yes, the RT version, if you are HST registered |
| Public? | Yes, corporate existence is public information | Not in the same way, though HST registration can be verified |
The 15-Character CRA Number, Decoded
The Business Number is where most of the practical confusion sits, because people encounter it in two forms and assume they are different numbers. They are not. The 9-digit BN is the root, and everything else is an extension of it.
| Part | Example | What It Is |
|---|---|---|
| Business Number | 123456789 | The 9-digit root. Identifies your legal entity to the CRA. Never changes. |
| Program identifier | RT | Two letters saying which type of account this is |
| Reference number | 0001 | Four digits distinguishing multiple accounts of the same type |
| Full account number | 123456789 RT0001 | What you quote when filing or paying that specific return |
The program identifiers that matter
| Code | Account | When You Need It |
|---|---|---|
| RC | Corporate income tax | Every corporation. This is what your T2 is filed against. |
| RT | GST/HST | Once taxable supplies exceed $30,000 over four consecutive calendar quarters, or on voluntary registration |
| RP | Payroll | Before you pay anyone a salary, including yourself |
| RM | Import/export | If you import or export goods |
| RZ | Information returns | For certain information return filings |
This is why "what is my HST number" has a confusing answer. Your HST number is your Business Number plus the RT account: 123456789 RT0001. The 9-digit root is the BN. When a customer asks for your HST number they want the full 15-character RT version, because that is the number that supports their input tax credit claim. Giving them the bare 9 digits is not enough.
The Gap That Causes First-Year Problems
Here is the part worth reading twice, because it is where new corporations get hurt and it is entirely preventable.
When you incorporate federally, a Business Number is generally created for you, usually with an RC account for corporate income tax. That feels like the CRA side is handled. It is not. You have a BN and one account. You do not have a payroll account. You do not have a GST/HST account. Nothing in your incorporation paperwork mentions this, and no one tells you, because the registry that incorporated you has no role in your tax accounts.
So the owner pays themselves a salary in month two, because that is what you do when you have a corporation. There is no RP account, so there is nowhere to remit the source deductions. By the time anyone notices, the remittance is late, and payroll penalties start at 3% on day one with no grace period. The same pattern repeats with HST: the business crosses the threshold, keeps invoicing, and charges HST without an RT account behind it.
Do this before your first filing obligation, not after. Log into CRA My Business Account and look at which program accounts are actually open under your BN. It takes minutes. The gap between having a Business Number and having the accounts you need is invisible until a deadline arrives, and by then the penalty has already started running.
Which Number Goes Where
The quick reference. When a form, a customer or a bank asks for "your number", this is what they actually mean.
- T2 corporate return: filed against your RC account. The return also asks for your Corporation Number, because the CRA needs to know which legal entity is filing.
- GST/HST return: your RT account (123456789 RT0001)
- Payroll remittance: your RP account (123456789 RP0001)
- Invoices to customers: your RT number, if you are HST registered. Your customer needs it for their ITC claim.
- Corporate annual return: your Corporation Number, filed with the registry, not the CRA
- CRA My Business Account: your Business Number
- Business bank account: generally both, plus your incorporation documents
- Municipal business licence: a different thing entirely, from your city, and neither number replaces it
| What Is Asking | Number It Wants | Format |
|---|---|---|
| T2 corporate tax return | Business Number, RC account (Corporation Number also requested on the return) | 123456789 RC0001 |
| GST/HST return | Business Number, RT account | 123456789 RT0001 |
| Payroll remittance (PD7A) | Business Number, RP account | 123456789 RP0001 |
| Customer asking for your HST number | Business Number, RT account | 123456789 RT0001 |
| Corporate annual return (registry) | Corporation Number | Registry format |
| CRA My Business Account login | Business Number | 123456789 |
| Certificate of Incorporation | Corporation Number | Registry format |
| Business bank account opening | Generally both, plus incorporation documents | Both |
| Authorising a CPA as your representative | Business Number | 123456789 |
| Municipal business licence | Neither. A separate municipal process. | Not applicable |
Using the wrong number is not a harmless clerical error. A filing quoted against the wrong account can be rejected, misapplied, or simply match nothing, which delays processing and can produce a late-filing penalty on a return you filed on time. Payments are worse: the money leaves your account and lands somewhere other than where it was owed, so you are both out the cash and still in arrears.
One Entity, One BN, Many Accounts
A recurring question is whether a growing business needs more numbers. Usually not. One corporation has one Business Number, and everything else is an account under it. Add payroll, and you add an RP account to the same BN. Register for HST, and you add RT. Start importing, add RM. The 9-digit root never changes.
What does require a second BN is a second legal entity. If you incorporate a holding company, that is a different corporation, so it has its own Corporation Number from the registry and its own BN from the CRA. Operating names do not create entities: you can register three trade names under one corporation and you still have one Corporation Number and one BN. The number attaches to the legal person, not to the branding.
What Happens at Wind-Down
The distinction matters most at the end, and this is where it costs people. Dissolving your corporation with the registry ends its legal existence and retires the Corporation Number. It does absolutely nothing to your CRA accounts. The BN and every program account under it stay open, still expecting returns, and final returns are still required.
Owners dissolve at the registry, consider the company closed, and stop filing. The CRA accounts remain open, and the file does not quietly go away. Closing the corporation properly means both: the registry dissolution and the CRA account closures, in the right order, with final returns filed.
Case Study: Incorporated in January, Late by March
An Ontario consultant incorporated federally, received the Certificate of Incorporation, and started work. A Business Number with an RC account was created automatically, which the owner reasonably read as the CRA being taken care of. In February, they paid themselves a first salary. No RP account existed, so the source deductions had nowhere to go, and the remittance was late before anyone knew there was a remittance to make. By spring they had also crossed the HST threshold and were invoicing with tax on the invoices and no RT account behind it. Neither error was caught by the software or by the registry, because neither is looking. We opened the correct program accounts, brought the remittances current, registered the RT account and corrected the invoicing position. The figures here are illustrative of the work we do, not a specific client file. Incorporation Services →
We Set Up Both Sides Properly
Incorporation is the legal step. The CRA accounts are the part that makes you able to file. We handle both, so your first year does not start with a penalty. Flat fee, including HST.
Incorporation
Federal or Ontario incorporation, NUANS name search, Articles, minute book and your Corporation Number.
CRA Account Setup
Business Number confirmed and the program accounts you actually need opened: RC, RT and RP, before the obligations arrive.
Ongoing Filing
T2, GST/HST and payroll filed against the right accounts, on the right schedule, by a licensed CPA firm.
Frequently Asked Questions on Business Numbers and Corporation Numbers
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