Singapore's post codes are 6 digits because they're granular enough to specify exact buildings -- it's possible to receive mail addressed to "John Tan, S(123456

Singapore's post codes are 6 digits because they're granular enough to specify exact buildings -- it's possible to receive mail addressed to "John Tan, S(123456)". Australia's post codes, on the other hand, are really wide. The entirety of central Sydney is all "2000" and mine covers around 6 city suburbs.