Do I need a Business Number? A CPA's guide to when, why, and how

The Business Number is one of those pieces of Canadian tax infrastructure that nearly every owner eventually has to deal with, but few understand clearly before they need it. The CRA's documentation is thorough, but it's structured the way the agency thinks rather than the way owners think. If you've ever landed on the CRA's Business Number page and come away with more questions than you started with, that's why. We have a much easier to follow resources guide here.

This guide walks through what the Business Number is, when you need one, how program accounts attach to it, how provincial identifiers fit in, and how to register.

What the Business Number actually is

The Business Number (BN) is a nine-digit identifier the CRA issues to any business that needs to interact with the federal tax system. It is not a tax account on its own. It is a master identifier that federal tax accounts attach to, similar to how your SIN identifies you across the federal government.

Program accounts are identified by a two-letter suffix appended to the nine-digit BN, followed by a four-digit reference number. A single BN can have many program accounts attached to it. The three most common:

• RT for GST/HST. Register once your taxable sales exceed the $30,000 small supplier threshold over four consecutive quarters, or voluntarily before that point.
• RP for payroll source deductions. Required before you run your first payroll.
• RC for corporate income tax. Used by the CRA for T2 filings. If you incorporated, an RC account was almost certainly created automatically.

Others exist (RM for import/export, RR for registered charities, RZ for T5 information returns), but for most growing Canadian businesses, RT, RP, and RC are the three that matter.

The four identifiers owners confuse constantly

Canadian businesses can end up with several different numbers issued by different levels of government, and they often get referred to using the same informal language.

Business Number (BN). Federal. CRA-issued. Nine digits. Used for CRA program accounts.

Corporation Number. Federal or provincial, issued by the incorporation authority (Corporations Canada for federal, your provincial registrar for provincial). Not a tax number. It identifies your corporation as a legal entity.

Business Identification Number (BIN). Ontario-specific. Issued by ServiceOntario when you register a sole proprietorship, partnership, or business name. An Ontario sole proprietor with a registered business name, no employees, and under $30,000 a year in revenue will have a BIN and no BN.

Numéro d'entreprise du Québec (NEQ). Quebec-specific. A ten-digit number from the Registraire des entreprises that every Quebec business must have.

When an owner tells us they "need their business number" and can't find it, the first thing we ask is which one. It's surprisingly often the corporation number they're looking for, not the BN.

Do you actually need a Business Number?

The short answer: you need a BN the moment you need to open a CRA program account. The real question is whether you need any of the program accounts.

You need a BN if any of these apply:

• You're about to cross the $30,000 small supplier threshold for GST/HST, or you've chosen to register voluntarily. Voluntary registration matters more than most owners realize. If your customers are themselves registrants, charging them GST/HST costs them nothing (they claim it back as an input tax credit), and voluntary registration lets you claim input tax credits on your own business expenses. Our GST/HST obligations guide covers when this calculation tips in your favour.
• You're about to hire your first employee.
• You incorporated, federally or provincially. An RC program account is typically created automatically at incorporation, which means you already have a BN.
• You're importing or exporting goods commercially.

You don't need a BN if you're a sole proprietor under $30,000 in annual taxable revenue, have no employees, don't import or export commercially, and report business income on your personal T1 via form T2125.

According to Zenbooks' Technology in Accounting study, 62% of Canadian small business owners still handle their own bookkeeping, which is usually where the BN confusion first surfaces: they register for GST/HST, then months later realize they needed to tell their bookkeeping software about the account structure, or they hire their first employee without setting up an RP account in advance.

"The most common mistake I see with new clients isn't that they forgot to register for a BN. It's that they registered for one program account, assumed they were done, and then tripped over the others six months later when payroll started or their first import showed up at the border." Albert Park, CPA, CA, CPA (IL), MTax, Senior Tax Manager, Zenbooks

How to register for a Business Number

Four ways to register, and the right one depends on your situation.

Automatic registration through incorporation. If you incorporate federally through Corporations Canada or provincially, your BN is typically issued automatically along with an RC program account. The BN appears on the confirmation documents.

Business Registration Online (BRO). The CRA's self-service portal for registering a new BN and up to four program accounts in one session. Most common path for sole proprietors and partnerships. Available on canada.ca.

My Business Account. If you already have a BN and need to add a program account, use My Business Account. Also where you'll manage ongoing filings and CRA correspondence.

By phone or mail. The CRA still accepts BN registrations through the Business Enquiries line and by mail using Form RC1. Slower but sometimes unavoidable for situations the online portal can't handle.

Whichever path you take, have ready: legal business name, business address, description of business activity, fiscal year-end, incorporation details if applicable, and estimated revenue or payroll figures. Online registrations typically process within a few business days.

Where to find your Business Number if you already have one

If you've registered, the BN appears on:

• CRA correspondence. Upper right, usually with the program account suffix relevant to that letter.
• CRA My Business Account. Displayed prominently once you log in.
• T2 corporate income tax return. First page, identification section.
• GST/HST return (Form GST34). The BN with RT suffix.
• T4 Summary filed with the CRA. The BN with RP suffix.
• Incorporation documents. On the certificate of incorporation if your BN was issued at incorporation.

If none of those sources are accessible, calling the CRA Business Enquiries line with your legal business name and address will usually get you the BN over the phone once you've verified identity.

The provincial layer: what else you might need

A BN handles your federal tax obligations. It doesn't handle everything.

In Ontario, sole proprietorships and partnerships register a business name with ServiceOntario and receive a BIN; corporations receive an Ontario corporation number. In Quebec, every business must register with the Registraire des entreprises for an NEQ, and QST collection requires separate registration with Revenu Québec. In British Columbia, BC corporations receive an incorporation number from BC Registry Services, and PST requires separate registration. Alberta has no provincial sales tax; Saskatchewan and Manitoba each have their own PST regimes requiring separate registration.

The Atlantic provinces (New Brunswick, Nova Scotia, PEI, Newfoundland and Labrador) use HST, which is administered federally through the CRA with your federal RT account. The territories have no territorial sales tax.

The pattern: the federal BN is always the same, the provincial identifiers are separate, and sales tax is sometimes federal (GST/HST) and sometimes provincial (PST, QST). An Ontario-incorporated business that sells into BC will have a federal BN, an Ontario corporation number, a federal RT account for HST, and a BC PST registration. Four numbers across two levels of government, for what feels like one business.

What a properly-set-up BN structure looks like in practice

The cases that go well share three traits. First, the owner understands which program accounts they have and which they'll need next, rather than discovering them reactively. Second, the BN and program account suffixes are consistently recorded in their accounting software, payroll provider, and banking records, so every remittance references the correct account. Third, someone is actively monitoring CRA correspondence through My Business Account rather than waiting for paper letters.

Our client Menos, which scaled from $156K in revenue in 2018 to over $12M by 2025, is a useful example. They came to us with delayed filings and a multi-account CRA structure that had grown messy as they expanded. Cleaning up the BN and program account structure so every remittance tied to clean, reconciled data was the foundation everything else was built on. The same principle applied to Boutique La Muse, which grew from $800K to $3.8M in sales: once the BN program account structure was stabilized and connected to automated systems, the owner's time stopped going to compliance and started going to growth.

FAQs

How do I register for a Business Number in Canada?

Most Canadian businesses register through the CRA's Business Registration Online portal at canada.ca, which lets you register your BN and up to four program accounts in one session. If you've incorporated, a BN and RC program account are typically issued automatically as part of incorporation. You can also register by phone through the CRA Business Enquiries line or by mail using Form RC1.

Where can I find my Business Number?

If you've registered, your BN appears on CRA correspondence (usually upper right), in My Business Account, on your T2 corporate return, on your GST/HST returns, on your T4 Summary, and on your incorporation documents.

Is a Business Number the same as a corporation number?

No. The Business Number is a federal CRA identifier used for tax program accounts. The corporation number is issued by the incorporation authority (Corporations Canada or your provincial registrar) and identifies your company as a legal entity.

Do sole proprietors need a Business Number?

Only if they need a CRA program account. A sole proprietor under $30,000 in annual revenue with no employees who isn't importing or exporting doesn't need a BN.

What's the difference between a Business Number and a GST/HST number?

A GST/HST number is your BN with the RT0001 (or higher reference) suffix attached. The nine-digit root is the BN; the RT suffix identifies the specific program account.

Can I have more than one Business Number?

A single legal entity has one BN. One BN can have many program accounts attached. If you operate multiple separate legal entities, each has its own BN.

How long does it take to get a Business Number?

Online registrations through Business Registration Online typically process within a few business days. Phone registrations are often faster for straightforward cases. Mail registrations using Form RC1 can take several weeks.

Where to go next

For the broader context on how the BN fits into the rest of your Canadian small business compliance stack, our Canadian Small Business Resources hub brings the federal and provincial requirements together in one place.