Canada Post and Forward Sortation Area and Local Delivery Unit

Canadian postal codes are broken down into two parts. The first three alphanumeric characters are for the FSA – or forward sortation area. The second group of three alphanumeric characters are for the LDU, or local delivery unit.

An overall geographical region where all the postal codes start with the same three characters is denoted as a forward sortation area. Outside of Ontario and Quebec, the first letter of a forward sortation area is for an individual postal district that encompasses an entire province. In Ontario and Quebec, they have eight total postal districts reflecting their larger population centres.

In the FSA, the digit helps specify whether the FSA is an urban or rural postal district. If the FSA contains a zero, this means it covers a wide rural area region. While the final character in an FSA the second letter, points to specific rural regions, an entire medium-sized city, or even a section of a larger major metropolitan area like Toronto.

The last three alphanumeric characters of a Canadian postal code are for the local delivery unit. This specifies a single address or range of addresses. This corresponds to an entire small town, a single side of city block, a single large building, individual institutions like hospitals, and it can even help specify very large businesses which regularly deal in huge volumes of mail.

Local delivery units that end with a zero character specify postal facilities of all types. LDUs can be a reserved for a specific postal mail carriers’ route.

In the Canadian postal code system, no postal code will contain the letters D, F, I, O, Q, or U. This exclusion is purposeful, as the automated mail-sorting units may confuse them with other letters and digits. Not everyone has clear handwriting! With only about twelve percent of all possible 850,000 active postal codes being used, there is plenty of room left to grow.