Australia Postal Code Format Guide
Australian postcodes contain four digits. The leading digits broadly correspond to state or territory routing, but special-purpose codes also exist.
Standard format
NNNN
Example
2000
Implementation and validation notes
Australian postcodes contain four digits. The leading digits broadly correspond to state or territory routing, but special-purpose codes also exist.
Validate required state, character set, length, and syntax on the client, then repeat validation on the server. Preserve the original input and normalize into a separate field; never truncate local scripts, compound names, or leading zeroes to fit a single Western assumption.
This guide describes common formats rather than an official registry and cannot enumerate every exception. Generated output is for testing only, not delivery, calling, identity verification, or real account activity.
Related resources
Frequently asked questions
What is the standard Australia postal code format?
A common representation is NNNN, for example 2000. Australian postcodes contain four digits. The leading digits broadly correspond to state or territory routing, but special-purpose codes also exist.
How should Australia postal code test data be stored?
Store the original value as a string so leading zeroes, spaces, hyphens, accents, and local scripts are preserved. Use a separate normalized field for search.
Does correct formatting prove the data is real?
No. Syntax validation cannot prove an address is deliverable, a number is assigned, or a name belongs to a real person.