About Australia Post Barcodes
The Australia Post barcode is a 4-state postal barcode used in Australia for sorting and tracking mail. Standardized by Australia Post, this barcode allows bulk mailers to print routing and customer-defined information on envelopes, enabling automated sorting down to specific carrier delivery routes throughout Australia.
How Australia Post Encoding Works
The barcode uses four vertical states: Tracker, Ascender, Descender, and Full Bar. It can be printed in three different formats (Standard, Customer Barcode 2, and Customer Barcode 3) depending on data length. It encodes an 8-digit Delivery Point Identifier (DPID) and a variable-length customer field that can store numeric codes or alphanumeric data, ending with a Reed-Solomon checksum.
Common Applications and Industries
Australia Post barcodes are printed on invoices, subscription media, marketing letters, and business correspondence in Australia. Australian organizations use them to claim bulk postage discounts. The customer data field allows utilities and banks to encode billing reference numbers, which are scanned and returned for accounting.
Advantages & Limitations
It supports custom alphanumeric data fields, allowing businesses to track internal reference codes alongside delivery routing in a single barcode. The Reed-Solomon checksum provides high security. The limitation is that it is restricted to the Australian postal network and requires specialized software to map postcodes to DPIDs.