Australian postcodes have four digit number format.
The first digit of Australian postcodes usually stands for a state or a territory. On this page you may see the list of Australian postcode ranges for each state. But some exceptions to these Australian postcode ranges take place in state or territory borders.
The second digit of Australian postcodes usually indicates a region within the state. Australian postcodes with a second digit of 0 or 1 are located within the metropolitan area of the state's capital city. Australian postcodes with other second digits are located in rural or regional areas.
Main Australian cities or towns usually have zero or two zeros at the end of their postcodes. But exceptions also occur.
Australian postcodes carry routing information. A postcode is often associated with a single geographical area (town or suburb). Some geographical areas in Australia have two postcodes. One is for Post Office Boxes, another is for street deliveries. Some departments or corporations that receive a lot of mail have their own Australian postcodes.
Australian postcodes are written at the end of the address after the city (suburb or town) and the state (or territory).