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Home > Guides > Canadian postal code structure
Every Canadian postal code follows the pattern letter-number-letter, space, number-letter-number. The first three characters form the forward sortation area: the first letter names a province or region, the digit after it separates urban from rural, and the third narrows the district. The last three characters are the local delivery unit, which points to a specific street, building, or rural route.
The first half of the code (the ANA part) tells the sorting machines which part of the country the mail is headed to. Take M4W 1A1. The M says Ontario, specifically the Toronto area. The 4 narrows it within that region, and the W narrows it further, down to a particular district. By the time the machines have read three characters, the letter is in the right city and nearly at the right depot.
The first letter maps to provinces and territories in a pattern that runs roughly east to west:
| First letter | Province or territory |
|---|---|
| A | Newfoundland and Labrador |
| B | Nova Scotia |
| C | Prince Edward Island |
| E | New Brunswick |
| G, H, J | Quebec |
| K, L, M, N, P | Ontario |
| R | Manitoba |
| S | Saskatchewan |
| T | Alberta |
| V | British Columbia |
| X | Northwest Territories and Nunavut |
| Y | Yukon |
This one is the urban-rural switch. A zero in the second position means a rural area: the mail goes to a rural route, a retail postal outlet, or a small community served from a nearby town. Any other digit means urban, with mail delivered by letter carriers or to community boxes. So K0A is a rural pocket of eastern Ontario, while K1A is downtown Ottawa. If you have ever wondered why some small towns share a postal code with the countryside around them, this is why.
The last three characters (the NAN part) zoom all the way in: a specific street segment, one side of one block, a single large building, or a rural route. This is the part that tells the carrier exactly where to walk. Two houses across the street from each other can share the first five characters and differ only in the last one.
Six letters are missing from the alphabet of postal codes: D, F, I, O, Q, and U. They were left out deliberately because they are too easy to confuse with digits or with each other on handwritten mail: O with zero, I with one, and so on. The alternating letter-number pattern itself was chosen for the same reason, so that a smudged character is still guessable from its position. It is a small piece of 1970s design thinking that still works.
H0H 0H0, Santa Claus, North Pole. Canada Post has run a Santa letter program for decades, and that code routes children's letters to the volunteer elves who answer them. Note the second character: a zero, which technically marks it rural. The North Pole, it turns out, is a rural delivery point.
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