Canadian Postal Codes: Format, Structure, and How They Work
Complete guide to Canadian postal codes. Learn the A1A 1A1 format, what each character means, and how to validate Canadian addresses in your software.
Overview of Canadian Postal Codes
Canada uses one of the most distinctive postal code systems in the world. The alphanumeric format — alternating letters and digits — provides precise geographic targeting and is a key element of the Canadian address system. Developers building address forms for Canadian users must understand this format thoroughly.
The Format: A1A 1A1
Canadian postal codes follow a strict six-character pattern with a space in the middle:
[Letter][Digit][Letter] [Digit][Letter][Digit]
Example
M5V 3L9
The first three characters form the **Forward Sortation Area (FSA)**, and the last three form the **Local Delivery Unit (LDU)**.
Forward Sortation Area (FSA)
The first three characters identify a geographic region:
First Letter - Province/Territory
The first letter indicates the province or territory:
| Letter | Province/Territory |
|--------|--------------------|
| A | Newfoundland and Labrador |
| B | Nova Scotia |
| C | Prince Edward Island |
| E | New Brunswick |
| G | Eastern Quebec |
| H | Montreal area |
| J | Western Quebec |
| K | Eastern Ontario |
| L | Central Ontario |
| M | Toronto |
| N | Southwestern Ontario |
| P | Northern Ontario |
| R | Manitoba |
| S | Saskatchewan |
| T | Alberta |
| V | British Columbia |
| X | Northwest Territories, Nunavut |
| Y | Yukon |
Note that D, F, I, O, Q, U, W, and Z are **never used** as the first letter.
Second Character - Urban/Rural
The second character (a digit) indicates whether the area is urban or rural:
0 = Rural area
1-9 = Urban area
Third Character
The third character (a letter) further narrows the geographic area.
Local Delivery Unit (LDU)
The last three characters (digit-letter-digit) identify a specific block face, building, or mail route within the FSA.
Letters Never Used
The letters **D, F, I, O, Q, and U** are excluded from all positions in Canadian postal codes. This prevents confusion with digits (O/0, I/1) and avoids certain letter combinations.