Postcodes in Australia

Postcodes in Australia are used to more efficiently sort and route mail within the Australian postal system.

Australian envelopes and postcards often have four square boxes printed in orange at the bottom right for the postcode.

The first digit for each state's postcode was copied directly from Australian radio call signs.

Over time, digits beyond this set have come to be used for PO Boxes etc., for example the 8000 series refers to special addresses in Victoria.

It is sometimes stated that the numbering was based on the (now retired) Australian Military Administrative Districts, however this is incorrect.

Due to postcode rationalisation, they can be quite complex, especially in country areas (e.g. 2570 belongs to twenty-two towns and suburbs around Camden, New South Wales).

For example, a street address in the Sydney suburb of Parramatta would be written like this: But mail sent to a PO Box in Parramatta would be addressed: Many large businesses, government departments and other institutions receiving high volumes of mail had their own postcode as a Large Volume Receiver (LVR), e.g. the Royal Brisbane and Women's Hospital has the postcode 4029, the Australian National University had the postcode 0200.

Three locations (Mingoola,[5] Mungindi[6] and Texas[7]) straddle the NSW-Queensland border (so same town name and postcode on both sides).

While these territories do not belong to any state, they are addressed as such for mail sorting: Three scientific bases in Antarctica operated by the Australian National Antarctic Research Expeditions share a postcode with the isolated sub-Antarctic island of Macquarie Island (part of Tasmania): There is also a "special" postcode for routing mail sent to Santa: Each state's capital city ends with three zeroes, while territorial capital cities end with two zeroes.

As an example, postcodes in the range 2200–2299 are split between the southern suburbs of Sydney and the Central Coast, Lake Macquarie and Newcastle regions of New South Wales.

Within each region with the same second numeral, postcodes are usually allocated in ascending order the further one travels from the state's capital city along major highways and railways.

For instance, heading north on the North Coast railway in New South Wales away from Sydney: Major towns and cities tend to have "0" as the last numeral or last two numerals, e.g. Rockhampton, Queensland has the postcode 4700 and Ballarat, Victoria has the postcode 3350.

Transport for NSW uses postcodes to give specific numbers for each bus stop in Greater Sydney.

Australian Bureau of Statistics, Australian Taxation Office and many other Federal and State government organisations publish a variety of statistics by postcode which extends the use Australia Post four digit code to many business and social planning related activities.