Canada Post Address Format: Unit/# vs PMB vs PO Box

Quick answer

Canada Post's standard business address format puts the unit number first, joined to the street number with a hyphen, written in uppercase block letters: 100-10 KING ST W, TORONTO ON M5X 1A1. PO Box numbering (PO BOX 1234) and PMB numbering (PMB 456) look similar but get rejected by the CRA, the federal and provincial business registries, and Canadian banks. If your virtual mailbox issues you anything other than a real Unit/# address, the format itself can fail your incorporation filing.

The exact Canada Post format your address should use

Canada Post publishes a standard for addressing all business and residential mail in Canada. Senders, registries, and Canadian banks all expect the same shape. There are three lines and five formatting rules, and getting any of them wrong can route your mail back to the sender or fail a registry filing.

The three-line structure:

ADDRESSEE NAME
UNIT-STREET NUMBER STREET NAME
CITY PROVINCE POSTAL CODE

A real example for a Toronto virtual mailbox address looks like this:

JANE SMITH
100-10 KING ST W
TORONTO ON  M5X 1A1

The five formatting rules Canada Post enforces:

These rules come straight from Canada Post's published Addressing Guidelines. The two-space rule before the postal code is the single most-missed detail, and it's the reason mail-sorting systems sometimes treat otherwise-correct addresses as undeliverable.

Why PO Box numbering gets rejected for business use

A Canada Post PO Box looks like this:

JANE SMITH
PO BOX 1234 STN A
TORONTO ON  M5W 1G6

STN A is the Canada Post sortation station. The address has no street number and no unit number. From the perspective of every Canadian institution that verifies business addresses, the absence of a real street number is the disqualifying detail.

Where PO Box format fails:

• The CRA. The Canada Revenue Agency requires "a physical address where the business is located" on a registered business. A PO Box is a postal handling reference, not a physical address. PO Boxes are accepted only as a mailing address in addition to a separate physical address — never as the sole address on a corporation file.
• Federal incorporation (Corporations Canada). Federal CBCA filings require a registered office that is a real, deliverable street address inside Canada.
• Ontario and BC business registries. Both provincial registries reject PO Boxes as registered offices. The address must be a real commercial or residential street address inside the province.
• Canadian bank account openings. RBC, TD, BMO, Scotiabank, and CIBC all run their compliance check against the registered office on file with the registry. A PO Box on a bank application either gets converted to a "mailing address only" field or stalls the application entirely. We covered the bank side in Open a Canadian business bank account with a virtual address.
• Couriers (UPS, FedEx, DHL, Purolator). None of them deliver to Canada Post outlets. Their booking systems refuse PO Box addresses at the label-printing stage. If a sender forces a courier to ship to a PO Box, the package is held at a courier hub or returned.

A PO Box is a fine personal mail-receiving slot. It is not a business address.

PMB format vs Unit format — the trap most newcomers fall into

This is the format detail that catches founders who choose a virtual mailbox provider on price alone.

Some virtual mailbox providers — particularly those operating through retail-chain partners like UPS Store franchises, Staples printing centres, or Anytime Mailbox partner locations — issue addresses in PMB (Private Mailbox) format. The convention looks like this:

JANE SMITH
123 MAIN ST PMB 456
TORONTO ON  M5V 2X8

PMB 456 flags to Canada Post that suite 456 is a sub-rented mailbox compartment inside a retail outlet, not a stand-alone unit in a multi-tenant commercial building. The distinction matters because PMB addresses occupy a grey zone in Canadian regulatory practice.

The risk with PMB format:

• Some Canadian registries reject PMB addresses as registered offices, treating them as functionally equivalent to PO Boxes since the underlying premise is a sub-rented mailbox.
• Some accept them. The acceptance pattern is inconsistent and varies by registry, by examiner, and over time as compliance practice tightens.
• Banks have flagged PMB addresses on compliance reviews, particularly when the bank cross-references the address against commercial property records and finds a retail outlet rather than a leased unit.
• The format ambiguity is the risk you're carrying. A Unit/# address either works or it doesn't on the filing. A PMB address might work this year and fail next year, with no warning.

Three questions to ask a virtual mailbox provider before you sign up:

1. Is the address you issue formatted as Unit-StreetNumber StreetName or as StreetAddress PMB Number?
2. Has the address been used as a registered office on prior federal, Ontario, or BC filings without rejection?
3. Will you sign an authorization-to-receive-legal-documents letter naming me as the recipient, on the building's letterhead?

If the provider can't answer any of these clearly, the format ambiguity will land on your filing — not theirs.

Auteur issues addresses in standard Unit/# format at both Toronto and Vancouver locations, and supports their use as registered offices for federal, Ontario, and BC incorporation.

Common formatting mistakes that route mail back to senders

The Canada Post format is unforgiving on a small number of details, and the same handful of mistakes show up over and over.

Apartment number written first as Apt #100. Canadians who grew up writing residential addresses sometimes default to Apt 100, 10 King St W. Canada Post's machine-readable format is 100-10 KING ST W — unit first, hyphen, street number, no comma, no "Apt" prefix. The "Apt # first" pattern surfaces frequently in r/CanadaPost threads as a source of returned mail.

Missing the two-space gap before the postal code. Canada Post's optical sorters expect exactly two spaces between the province abbreviation and the postal code. A single space sometimes still gets through, but in high-volume periods it can drop a piece into manual sortation, adding two to four business days.

Lowercase or mixed-case letters. Standard format is uppercase block letters throughout. Most modern sorters tolerate mixed case, but Canada Post's published guidance is uppercase, and that's what the registries and banks expect to see in their database.

Punctuation inside the street line. Commas after the street name, periods after St., or # before the unit number are all out-of-spec. The clean version is 100-10 KING ST W — a hyphen, a space, and that's it.

Postal code typed as M5X1A1. The postal code requires one internal space in the LDL DLD shape. M5X1A1 is read by Canada Post as malformed and may stall in sortation.

"Suite" vs "Unit" vs nothing. Canada Post's preferred convention is no prefix — just 100-10 KING ST W. If you must include a prefix, UNIT 100 is more common than SUITE 100 in residential and small-commercial addressing. APT 100 is correct for residential apartments only. None of these are required when you use the hyphen format.

Community mailbox, parcel locker, PO Box — what's actually different

These three terms get used interchangeably outside Canada Post's documentation, but they are three distinct things, and only one of them is your address.

Community mailbox. A multi-compartment mailbox installed at a curb in newer suburban developments, replacing door-to-door delivery for a residential block. Each household has a numbered compartment with a key. The address itself is the household's normal civic address — the community mailbox is just where the carrier physically deposits the mail. It is not a separate address.

Parcel locker (or parcel compartment). A larger compartment inside a community mailbox or apartment-building mailroom used for parcels too large for a regular mail slot. The carrier leaves a key inside the household's compartment that opens the parcel locker once. Like the community mailbox, this is a delivery mechanism, not an address.

PO Box. A numbered locker rented from Canada Post inside a post office. This is a separate address — but it's a Canada Post handling reference, not a street address, and it's the format the CRA, registries, and banks all reject for business use.

A virtual mailbox is none of these. It is a real commercial street address at a building staffed by a mailroom that receives, scans, forwards, or holds mail on your behalf. The address you give out is the same shape as any other commercial address in Toronto or Vancouver, with a normal civic number, street name, and unit number — nothing flagged in the address itself indicates that the receiver is a virtual mailbox provider.

What this means when you choose a provider

The format question is the cheapest, easiest disqualification to apply when you're comparing virtual mailbox providers. Two cities with similar headline pricing can issue addresses with completely different risk profiles on the filing side.

Before you sign up, confirm in writing:

• The address is issued in standard Unit/# format, not PMB format.
• The address is at a real commercial building leased or owned by the provider, not a retail-chain mailbox compartment.
• The address has been used as a federal, Ontario, or BC registered office on prior filings without rejection.
• The provider will sign a written authorization to receive legal and government documents on your behalf.

If any of those four answers comes back ambiguous, you're carrying the format risk on your own filing.

For a deeper look at the address question across providers, see the 7 best virtual business address providers in Canada and the virtual address vs PO Box comparison. For the underlying CRA rule on what counts as a registered address, see Canadian business registered address: CRA requirements.

FAQs

How do I tell senders to format my virtual mailbox address?

Give them the three-line block in Canada Post format with the hyphen between unit and street number, uppercase letters, two spaces before the postal code, and the postal code in A1A 1A1 shape. For your name on the first line, use the legal name on file with the registry — "JANE SMITH" or "JANE SMITH CONSULTING INC." rather than a nickname or trade name. If you receive mail addressed to multiple business names at the same address, the mailroom can route by recipient name as long as the rest of the format is correct.

Is "Suite" or "Unit" preferred in Canada Post format?

Neither is required. Canada Post's machine-readable convention is the hyphen-joined form 100-10 KING ST W, with no prefix. If you choose to include a prefix for clarity in a digital signature or invoice, "Unit" is the more common choice in commercial Canadian addressing — "Suite" reads as more office-park than mailroom-compatible, and "Apt" is reserved for residential apartments. The hyphen format is the safest choice across registries and banks because it matches Canada Post's published spec exactly.

What if my current provider gives me a PMB-format address?

You have three options. First, check whether the registry that holds your registered office has flagged the address — open the corporation profile on the federal, Ontario, or BC registry and confirm the address-on-file format. If it reads as ... PMB 456 and the filing went through, you're operating in the grey zone but not currently rejected. Second, ask the provider directly whether they can issue you a Unit-format address at the same building or another building in their portfolio — many can, but only if you ask. Third, switch to a provider that issues addresses in Unit format from the outset. If you're moving anyway because of compliance concerns, reserve an Auteur address in Toronto or Vancouver — both cities use standard Unit/# format and both have been used as federal, Ontario, and BC registered offices.

Where to go from here

If you're choosing between formats and providers, the virtual address vs PO Box comparison walks through the same question from the PO Box side. If you're already comparing providers head-to-head, the 7 best virtual business address providers in Canada covers Unit/PMB format alongside city coverage and pricing. If you've decided you want a real Unit-format address in Toronto or Vancouver that the registries and banks will accept on the first try, reserve your Auteur address.