Do Canadian Small Businesses Need a Business Number?

Key takeaways

• A Business Number (BN) is not the same thing as a GST/HST account. The BN is the 9-digit identifier the CRA assigns once. GST/HST, payroll, import/export, and corporate income tax are separate program accounts attached to that same BN, each with its own 2-letter suffix.
• Sole proprietors below the $30,000 small supplier threshold, with no employees and no import/export activity, do not need a BN at all. The BN is triggered by what you register for, not by simply running a business.
• Incorporated companies receive a BN automatically. Federal, Ontario, and BC incorporations all return a Business Number as part of the incorporation output — corporations almost never apply for a BN separately.
• The CRA writes a mailing address onto the BN file. Any Canadian street address that receives registered mail satisfies the requirement; PO boxes do not. Using the same address across the BN file, the GST/HST account, and the corporate registry prevents the address-mismatch flags that delay correspondence.

Short answer

You need a Canadian Business Number (BN) the moment you register for a CRA program — GST/HST, payroll, import/export, or corporate income tax. Sole proprietors who stay under the $30,000 small supplier threshold, employ no one, and don't import or export goods can run a legal business without ever applying for one. Incorporated companies receive a BN automatically as part of incorporation. The fastest way to get a BN when you do need one is Business Registration Online (BRO) on the CRA portal.

The practical question for most founders is therefore not "do I need a BN" but "which program accounts do I need, and what address goes on the file?"

What a Business Number actually is — 9 digits, 2 letters, and the four program accounts

A Business Number is a single 9-digit identifier the Canada Revenue Agency assigns to your business. That number stays the same for the life of the business. What changes is the set of program account suffixes the CRA attaches to it whenever you register for a specific federal program.

The full account number reads as: 123456789 RT 0001 — nine digits, then a two-letter program identifier, then a four-digit reference for that specific account.

The four common program identifiers:

Other program identifiers exist for narrower cases (RD for excise duty, RG for Air Travellers Security Charge, RR for registered charities and amateur athletic associations), but the four above cover almost every Canadian small business situation.

The reference number on the end (0001, 0002, etc.) lets one BN hold multiple accounts of the same type. A corporation operating in two provinces with separate payroll cycles can have RP 0001 for one and RP 0002 for the other under the same BN.

BN vs "CRA number" — a terminology note. "CRA number" is sometimes used loosely as a synonym for the Business Number. The BN is the 9-digit identifier on the business side. A corporation's corporate income tax account (RC 0001) is a program account off the BN, not a separate identifier. When someone in a business context asks for "your CRA number," they almost always mean the 9-digit BN; on a personal tax form, the same phrase usually points at your Social Insurance Number instead.

Who actually needs a Business Number — and who doesn't

The CRA's own guidance is more precise than most online summaries. A BN is required only when you register for at least one program account. Many Canadian sole proprietors and small partnerships operate legally for years without one.

You need a BN if any of the following apply:

• You incorporate (federal CBCA, Ontario OBCA, BC BCBCA, or any other provincial Act) — the incorporation process automatically opens an RC corporate income tax account, and you receive the BN as part of the incorporation output
• You register for GST/HST — voluntarily before the $30,000 threshold or mandatorily once you cross it (see our guide to GST/HST registration for Canadian small businesses for the exact threshold rules)
• You hire your first employee — payroll registration (RP) is required before the first paycheque clears
• You import or export commercial goods across the Canadian border
• You're a non-resident doing business in Canada and need to file Canadian returns or claim Canadian tax obligations

You do not need a BN if all of the following are true:

• You operate as a sole proprietor or general partnership
• Your worldwide taxable revenue is under the $30,000 small supplier threshold
• You have no employees on payroll
• You don't import or export commercial goods
• You aren't claiming GST/HST input tax credits voluntarily

Most one-person consultancies, side-business freelancers, and pre-revenue ventures fall into the second category and can run for an entire fiscal year on a Social Insurance Number alone, reporting business income on the T2125 Statement of Business Activities attached to their personal T1 return.

The moment any one of the BN triggers fires, the BN itself becomes mandatory before you can complete the program registration. There's no in-between state where you have, for example, a payroll account without a BN.

Sole proprietor vs corporation — why the BN question splits in two

Sole proprietors and corporations approach the BN from opposite directions, and the difference confuses founders who switch from one to the other partway through their first year.

Sole proprietors apply for a BN only when they need a program account. No incorporation paperwork, no automatic registration. The Business Registration Online form asks what program accounts you want to open at the same time, and the BN gets created in the same submission. If you only need GST/HST, you walk out with a BN and an RT 0001 account. If you only need payroll, you walk out with a BN and an RP 0001 account.

Corporations get a BN automatically as part of incorporation. The federal Corporations Canada portal and the Ontario and BC corporate registries all push the new corporation's information into the CRA the same day, and the corporation's RC 0001 corporate income tax account opens automatically. By the time you log into My Business Account the day after incorporating, the BN is already there with the corporate income tax account attached. Adding GST/HST or payroll later is a follow-up registration on the same BN.

A sole proprietor who later decides to incorporate does not transfer the existing BN. The corporation is a new legal entity and receives its own new BN. The sole proprietor's BN gets closed out, and any GST/HST or payroll accounts on the old BN are typically wound down and reopened under the new corporate BN. This is one of several reasons many founders incorporate earlier rather than later if growth is on the horizon — the cleanup of two separate BNs is a small but real annual expense.

For founders deciding which incorporation jurisdiction makes sense, our federal vs Ontario vs BC incorporation guide walks through the trade-offs. The BN itself is identical regardless of which province you incorporate in.

How to register a BN online — the BRO walkthrough

For sole proprietors and partnerships that aren't incorporating, Business Registration Online (BRO) is the fastest way to get a BN. Effective November 3, 2025, the CRA no longer accepts BN registrations by phone — only BRO and the paper Form RC1 by mail or fax remain. Online submissions return a BN immediately on screen; Form RC1 typically takes 4 to 6 weeks to process before the BN arrives by mail. Both options are free of charge — there is no registration fee for the BN itself or for opening program accounts (GST/HST, payroll, import/export) at the same time.

What BRO asks for:

1. Identification of the principal owner — name, Social Insurance Number, date of birth
2. Business legal structure — sole proprietorship, partnership, corporation (rare on BRO since corporations get a BN automatically), or trust
3. Business name — the operating name used on invoices and contracts
4. Business activity description — a plain-English summary of what the business does
5. Mailing address and physical location — see the address section below for what each field means
6. Program accounts to open at the same time — GST/HST (RT), payroll (RP), import/export (RM), or none
7. Fiscal year-end and effective date — most sole proprietors use December 31 to match the calendar year and personal T1 timing

A complete BRO submission returns the new BN immediately on screen. The first program account on the BN is opened in the same submission; any subsequent accounts are added through My Business Account or by phone.

What BRO doesn't ask for is also useful to know. There's no provincial registration in BRO — that happens separately at the provincial business registry. There's no NUANS name search — that's only required if you incorporate. And there's no fee at any stage — the BN itself is free, the BRO submission is free, and program account registrations are free.

What address goes on the BN application — and what the CRA actually checks

The BN application asks for two address fields, and they don't always need to be the same.

Mailing address. Where the CRA sends correspondence on paper — notices of assessment, audit letters, and program updates. This is the address that has to receive and accept registered mail.

Physical location of the business. Where the business actually operates. This can match the mailing address or differ from it.

What the CRA tests for. A real Canadian street address that can take delivery of registered mail and produce a signature on receipt. The address must be inside Canada. It must be capable of physical mail delivery — meaning it has a street number and a route Canada Post can serve.

What the CRA rejects. Post Office boxes (no physical delivery), parcel-locker numbers, and fictitious addresses. UPS-style mailbox numbers fall into a grey zone — some get accepted, others get flagged. The safer answer is a commercial street address that's recognized as a real business location.

A virtual address from a licensed commercial provider satisfies both fields. The same Toronto or Vancouver suite that serves as a corporation's registered office and as the mailing address on the GST/HST file can sit on the BN file too. Using one address across all three records keeps every CRA system in sync, removes the address-mismatch flags that slow down My Business Account access and bank reconciliation, and gives you a single inbox for every CRA letter.

The same-day mail scanning that comes with a proper virtual mailbox matters here for a specific compliance reason. CRA correspondence often carries tight reply windows — 30 days for objections, 90 days for some assessments — and a paper notice sitting in an unattended mailroom can quietly turn into a missed deadline. If the BN file's mailing address routes mail through a virtual mailbox with same-day digital delivery, the deadline clock starts on the day you actually receive the notice instead of the day someone happens to check the box.

If you're setting up a Canadian business address before arriving in Canada — a common pattern for newcomers and non-resident founders — the BN typically waits until you have a Canadian address on the file. Non-residents have a slightly different path: see the section below.

Adding GST/HST, payroll, and import/export accounts to your existing BN

Once the BN exists, adding new program accounts is straightforward. The same 9-digit number stays; what changes is the suffix.

Adding GST/HST (RT). Through My Business Account, by phone (1-800-959-5525), or by mailing Form RC1A. The RT account opens with reference number RT 0001. If you already crossed the $30,000 small supplier threshold, register before your next sale — the CRA treats you as registered from the day you exceeded the threshold, regardless of when the paperwork actually files. The full threshold rules are in our GST/HST registration guide.

Adding payroll (RP). Required before the first employee paycheque clears, including for an owner-manager paying themselves a T4 salary out of a corporation. The CRA expects payroll deductions to start on the first pay period — registering after the fact triggers interest on the late remittances.

Adding import/export (RM). Required before the first commercial shipment crosses the border. The Canada Border Services Agency uses the BN to identify the importer or exporter on commercial customs declarations.

Multiple reference numbers under one program. A corporation with two distinct payroll cycles, two GST/HST filing groups, or two import streams can run them as RP 0001 / RP 0002 or RT 0001 / RT 0002 under the same BN. Each reference number files its own returns, but the underlying business identity is one entity.

For non-residents, the path is different. A non-resident corporation registering for GST/HST or for the simplified digital-services regime uses Form RC1 plus RC1A by mail (BRO doesn't accept non-resident applicants directly), and a non-resident registrant must either have a permanent establishment in Canada or post security with the CRA. Our guide to opening a Canadian business bank account as a non-resident covers the upstream banking steps that usually run in parallel.

FAQ

Do I need a business number if I make less than $30,000?

Not unless something other than revenue triggers it. The $30,000 line is specifically the GST/HST small supplier threshold — below it, GST/HST registration is voluntary. The BN itself follows program registration: if you don't register for GST/HST and don't have employees, imports, or a corporation, you don't need a BN regardless of revenue. Many sole proprietors run for years on a Social Insurance Number alone, reporting business income on the T2125 form attached to their personal T1.

Do I need a business number for my small business?

It depends on the structure and the activity. If you're an incorporated company, you already have a BN — incorporation creates one automatically. If you're a sole proprietor or partnership, you need a BN only when you register for a program account: GST/HST, payroll, or import/export. A pre-revenue side business with no employees and no GST/HST registration can operate without a BN; the moment you hire someone, cross the GST/HST threshold, or import goods, the BN becomes mandatory before the program registration can complete.

What is the difference between RT0001 and RC0001?

RT0001 is a GST/HST account — the program identifier RT plus reference number 0001. It tracks the GST/HST you collect from customers and the input tax credits you claim on business expenses. RC0001 is a Corporate Income Tax account — program identifier RC plus reference number 0001. It tracks the corporation's federal income tax obligations under the T2 return. A federally or provincially incorporated company with GST/HST registration would have both, attached to the same 9-digit BN. The two accounts file separate returns on separate timelines.

Bottom line

The BN is the CRA's identity layer for businesses. It exists once per business, gets created either by incorporation or by your first program registration, and stays the same for the life of the entity. The complexity in the system is in the program accounts hanging off the BN, not the BN itself.

For sole proprietors, the practical question is whether any program account is triggered yet — GST/HST above $30k, payroll on the first employee, import/export at the border. For corporations, the BN is already there from day one and the only question is which program accounts to open and when.

Either way, the address on the BN file is the address on every CRA letter for the life of the business. Reserve a Toronto or Vancouver address before you register and the BN file, the GST/HST account, the corporate registry, and the bank account opening can all reference the same Canadian street address — with the same-day mail scanning that turns a 30-day CRA response window into a 30-day window instead of a 16-day one.